Patent Publication Number: US-9427532-B2

Title: Tissue penetration device

Description:
RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 13/692,168, filed Dec. 3, 2012, which is a divisional of U.S. Ser. No. 13/184,644, filed Jul. 18, 2011, which is a divisional of U.S. Ser. No. 11/317,912 filed Dec. 22, 2005 (now U.S. Pat. No. 8,016,774), which is a divisional of U.S. Ser. No. 10/127,395 filed Apr. 19, 2002 (now U.S. Pat. No. 7,025,774), which claims the benefit of U.S. Provisional Patent Application Ser. No. 60/298,055 filed Jun. 12, 2001; U.S. Provisional Patent Application Ser. No. 60/298,126 filed Jun. 12, 2001; U.S. Provisional Patent Application Ser. No. 60/297,861 filed Jun. 12, 2001; U.S. Provisional Patent Application Ser. No. 60/298,001 filed Jun. 12, 2001, U.S. Provisional Patent Application Ser. No. 60/298,056 filed Jun. 12, 2001; U.S. Provisional Patent Application Ser. No. 60/297,864 filed Jun. 12, 2001; and U.S. Provisional Patent Application Ser. No. 60/297,860 filed Jun. 12, 2001; all U.S. patent applications stated above being hereby incorporated by reference. 
     This application is also related to U.S. patent application Ser. No. 10/127,201 filed Apr. 19, 2002 and U.S. Patent Application Ser. No. 60/374,304 filed Apr. 19, 2002, both of which are hereby incorporated by reference in their entirety. 
    
    
     BACKGROUND 
     Lancing devices are known in the medical health-care products industry for piercing the skin to produce blood for analysis. Biochemical analysis of blood samples is a diagnostic tool for determining clinical information. Many point-of-care tests are performed using whole blood, the most common being monitoring diabetic blood glucose level. Other uses for this method include the analysis of oxygen and coagulation based on Prothrombin time measurement. Typically, a drop of blood for this type of analysis is obtained by making a small incision in the fingertip, creating a small wound, which generates a small blood droplet on the surface of the skin. 
     Early methods of lancing included piercing or slicing the skin with a needle or razor. Current methods utilize lancing devices that contain a multitude of spring, cam and mass actuators to drive the lancet. These include cantilever springs, diaphragms, coil springs, as well as gravity plumbs used to drive the lancet. Typically, the device is pre-cocked or the user cocks the device. The device is held against the skin and the user, or pressure from the users skin, mechanically triggers the ballistic launch of the lancet. The forward movement and depth of skin penetration of the lancet is determined by a mechanical stop and/or dampening, as well as a spring or cam to retract the lancet. Such devices have the possibility of multiple strikes due to recoil, in addition to vibratory stimulation of the skin as the driver impacts the end of the launcher stop, and only allow for rough control for skin thickness variation. Different skin thickness may yield different results in terms of pain perception, blood yield and success rate of obtaining blood between different users of the lancing device. 
     Success rate generally encompasses the probability of producing a blood sample with one lancing action, which is sufficient in volume to perform the desired analytical test. The blood may appear spontaneously at the surface of the skin, or may be “milked” from the wound. Milking generally involves pressing the side of the digit, or in proximity of the wound to express the blood to the surface. The blood droplet produced by the lancing action must reach the surface of the skin to be viable for testing. For a one-step lance and blood sample acquisition method, spontaneous blood droplet formation is requisite. Then it is possible to interface the test strip with the lancing process for metabolite testing. 
     When using existing methods, blood often flows from the cut blood vessels but is then trapped below the surface of the skin, forming a hematoma. In other instances, a wound is created, but no blood flows from the wound. In either case, the lancing process cannot be combined with the sample acquisition and testing step. Spontaneous blood droplet generation with current mechanical launching system varies between launcher types but on average it is about 50% of lancet strikes, which would be spontaneous. Otherwise milking is required to yield blood. Mechanical launchers are unlikely to provide the means for integrated sample acquisition and testing if one out of every two strikes does not yield a spontaneous blood sample. 
     Many diabetic patients (insulin dependent) are required to self-test for blood glucose levels five to six times daily. Reducing the number of steps required for testing would increase compliance with testing regimes. A one-step testing procedure where test strips are integrated with lancing and sample generation would achieve a simplified testing regimen. Improved compliance is directly correlated with long-term management of the complications arising from diabetes including retinopathies, neuropathies, renal failure and peripheral vascular degeneration resulting from large variations in glucose levels in the blood. Tight control of plasma glucose through frequent testing is therefore mandatory for disease management. 
     Another problem frequently encountered by patients who must use lancing equipment to obtain and analyze blood samples is the amount of manual dexterity and hand-eye coordination required to properly operate the lancing and sample testing equipment due to retinopathies and neuropathies particularly, severe in elderly diabetic patients. For those patients, operating existing lancet and sample testing equipment can be a challenge. Once a blood droplet is created, that droplet must then be guided into a receiving channel of a small test strip or the like. If the sample placement on the strip is unsuccessful, repetition of the entire procedure including re-lancing the skin to obtain a new blood droplet is necessary. 
     What is needed is a device, which can reliably, repeatedly and painlessly generate spontaneous blood samples. In addition, a method for performing analytical testing on a sample that does not require a high degree of manual dexterity or hand-eye coordination is required. Integrating sample generation (lancing) with sample testing (sample to test strip) will result in a simple one-step testing procedure resulting in better disease management through increased compliance with self testing regimes. 
     SUMMARY 
     Advantages can be achieved by use of a tissue penetration device that has user definable control of parameters such as lancet displacement, velocity of incision, retraction, acceleration, and tissue dwell time. A device having features of the invention can compensate for long-term changes in skin physiology, nerve function, and peripheral vascular perfusion such as occurs in diabetes, as well as diurnal variation in skin tensile properties. Alternatively, a device having features of the invention can compensate for skin differences between widely differing populations such as pediatric and geriatric patients, in addition to reducing the pain associated with lancing. 
     In one embodiment of the present invention, an agent injection device is provided that is capable of injecting an agent to a known predetermined tissue depth. An injection member has an elongate injection shaft with an outlet port configured to dispense an agent at a controllable time. A controllable driver is coupled to the elongate injection shaft and is configured to drive the injection member into target tissue. A velocity control system is in communication with the controllable driver and is configured to control the velocity of the elongate injection shaft. 
     In another embodiment of the present invention, a method is provided of injecting an agent into the tissue of a patient at a known predetermined depth. An elongate injection shaft having an outlet port configured to dispense an agent at a controllable time toward the patient&#39;s target tissue. A contact point is determined between a distal extremity of the elongate injection shaft and the target tissue. The elongate injection shaft is advanced into the target tissue from the contact point over a displacement equal to the sum of an elastic recoil displacement value for the target tissue, the distance between a distal extremity of the elongate injection shaft and the outlet port, and the desired tissue depth of injection for agent deposition. The agent is injected. 
     In another embodiment of the present invention, a method of injecting an agent into a patient&#39;s target tissue at a desired injection depth is provided. An elongate injection shaft is driven. The elongate injection shaft has an outlet port configured to dispense an agent at a controllable time toward the patient&#39;s target tissue. The elongate injection shaft is advanced into the target tissue from a contact point between the elongate injection shaft and the target tissue over a displacement greater than the desired injection depth to a position of maximum penetration. The injection shaft is withdrawn in a proximal direction to the desired penetration depth. The agent is injected. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1-3  are graphs of lancet velocity versus position for embodiments of spring driven, cam driven, and controllable force drivers. 
         FIG. 4  illustrates an embodiment of a controllable force driver in the form of a flat electric lancet driver that has a solenoid-type configuration. 
         FIG. 5  illustrates an embodiment of a controllable force driver in the form of a cylindrical electric lancet driver using a coiled solenoid-type configuration. 
         FIG. 6  illustrates a displacement over time profile of a lancet driven by a harmonic spring/mass system. 
         FIG. 7  illustrates the velocity over time profile of a lancet driver by a harmonic spring/mass system. 
         FIG. 8  illustrates a displacement over time profile of an embodiment of a controllable force driver. 
         FIG. 9  illustrates a velocity over time profile of an embodiment of a controllable force driver. 
         FIG. 10  illustrates the lancet needle partially retracted, after severing blood vessels; blood is shown following the needle in the wound tract. 
         FIG. 11  illustrates blood following the lancet needle to the skin surface, maintaining an open wound tract. 
         FIG. 12  is a diagrammatic view illustrating a controlled feed-back loop. 
         FIG. 13  is a graph of force vs. time during the advancement and retraction of a lancet showing some characteristic phases of a lancing cycle. 
         FIG. 14  illustrates a lancet tip showing features, which can affect lancing pain, blood volume, and success rate. 
         FIG. 15  illustrates an embodiment of a lancet tip. 
         FIG. 16  is a graph showing displacement of a lancet over time. 
         FIG. 17  is a graph showing an embodiment of a velocity profile, which includes the velocity of a lancet over time including reduced velocity during retraction of the lancet. 
         FIG. 18  illustrates the tip of an embodiment of a lancet before, during and after the creation of an incision braced with a helix. 
         FIG. 19  illustrates a finger wound tract braced with an elastomer embodiment. 
         FIG. 20  is a perspective view of a tissue penetration device having features of the invention. 
         FIG. 21  is an elevation view in partial longitudinal section of the tissue penetration device of  FIG. 20 . 
         FIG. 22  is an elevation view in partial section of an alternative embodiment. 
         FIG. 23  is a transverse cross sectional view of the tissue penetration device of  FIG. 21  taken along lines  23 - 23  of  FIG. 21 . 
         FIG. 24  is a transverse cross sectional view of the tissue penetration device of  FIG. 21  taken along lines  24 - 24  of  FIG. 21 . 
         FIG. 25  is a transverse cross sectional view of the tissue penetration device of  FIG. 21  taken along lines  25 - 25  of  FIG. 21 . 
         FIG. 26  is a transverse cross sectional view of the tissue penetration device of  FIG. 21  taken along lines  26 - 26  of  FIG. 21 . 
         FIG. 27  is a side view of the drive coupler of the tissue penetration device of FIG. 
         FIG. 28  is a front view of the drive coupler of the tissue penetration device of  FIG. 21  with the lancet not shown for purposes of illustration. 
         FIGS. 29A-29C  show a flowchart illustrating a lancet control method. 
         FIG. 30  is a diagrammatic view of a patient&#39;s finger and a lancet tip moving toward the skin of the finger. 
         FIG. 31  is a diagrammatic view of a patient&#39;s finger and the lancet tip making contact with the skin of a patient&#39;s finger. 
         FIG. 32  is a diagrammatic view of the lancet tip depressing the skin of a patient&#39;s finger. 
         FIG. 33  is a diagrammatic view of the lancet tip further depressing the skin of a patient&#39;s finger. 
         FIG. 34  is a diagrammatic view of the lancet tip penetrating the skin of a patient&#39;s finger. 
         FIG. 35  is a diagrammatic view of the lancet tip penetrating the skin of a patient&#39;s finger to a desired depth. 
         FIG. 36  is a diagrammatic view of the lancet tip withdrawing from the skin of a patient&#39;s finger. 
         FIGS. 37-41  illustrate a method of tissue penetration that may measure elastic recoil of the skin. 
         FIG. 42  is a graphical representation of position and velocity vs. time for a lancing cycle. 
         FIG. 43  illustrates a sectional view of the layers of skin with a lancet disposed therein. 
         FIG. 44  is a graphical representation of velocity vs. position of a lancing cycle. 
         FIG. 45  is a graphical representation of velocity vs. time of a lancing cycle. 
         FIG. 46  is an elevation view in partial longitudinal section of an alternative embodiment of a driver coil pack and position sensor. 
         FIG. 47  is a perspective view of a flat coil driver having features of the invention. 
         FIG. 48  is an exploded view of the flat coil driver of  FIG. 47 . 
         FIG. 49  is an elevational view in partial longitudinal section of a tapered driver coil pack having features of the invention. 
         FIG. 50  is a transverse cross sectional view of the tapered coil driver pack of  FIG. 49  taken along lines  50 - 50  in  FIG. 49 . 
         FIG. 51  shows an embodiment of a sampling module which houses a lancet and sample reservoir. 
         FIG. 52  shows a housing that includes a driver and a chamber where the module shown in  FIG. 51  can be loaded. 
         FIG. 53  shows a tissue penetrating sampling device with the module loaded into the housing. 
         FIG. 54  shows an alternate embodiment of a lancet configuration. 
         FIG. 55  illustrates an embodiment of a sample input port, sample reservoir and ergonomically contoured finger contact area. 
         FIG. 56  illustrates the tissue penetration sampling device during a lancing event. 
         FIG. 57  illustrates a thermal sample sensor having a sample detection element near a surface over which a fluid may flow and an alternative position for a sampled detection element that would be exposed to a fluid flowing across the surface. 
         FIG. 58  shows a configuration of a thermal sample sensor with a sample detection element that includes a separate heating element. 
         FIG. 59  depicts three thermal sample detectors such as that shown in  FIG. 58  with sample detection elements located near each other alongside a surface. 
         FIG. 60  illustrates thermal sample sensors positioned relative to a channel having an analysis site. 
         FIG. 61  shows thermal sample sensors with sample detection analyzers positioned relative to analysis sites arranged in an array on a surface. 
         FIG. 62  schematically illustrates a sampling module device including several possible configurations of thermal sample sensors including sample detection elements positioned relative to sample flow channels and analytical regions. 
         FIG. 63  illustrates a tissue penetration sampling device having features of the invention. 
         FIG. 64  is a top view in partial section of a sampling module of the tissue penetration sampling device of  FIG. 63 . 
         FIG. 65  is a cross sectional view through line  65 - 65  of the sampling module shown in  FIG. 64 . 
         FIG. 66  schematically depicts a sectional view of an alternative embodiment of the sampling module. 
         FIG. 67  depicts a portion of the sampling module surrounding a sampling port. 
         FIGS. 68-70  show in sectional view one implementation of a spring powered lancet driver in three different positions during use of the lancet driver. 
         FIG. 71  illustrates an embodiment of a tissue penetration sampling device having features of the invention. 
         FIG. 72  shows a top surface of a cartridge that includes multiple sampling modules. 
         FIG. 73  shows in partial section a sampling module of the sampling cartridge positioned in a reader device. 
         FIG. 74  is a perspective view in partial section of a tissue penetration sampling device with a cartridge of sampling modules. 
         FIG. 75  is a front view in partial section of the tissue penetration sampling device of  FIG. 56 . 
         FIG. 76  is a top view of the tissue penetration sampling device of  FIG. 75 . 
         FIG. 77  is a perspective view of a section of a sampling module belt having a plurality of sampling modules connected in series by a sheet of flexible polymer. 
         FIG. 78  is a perspective view of a single sampling module of the sampling module belt of  FIG. 59 . 
         FIG. 79  is a bottom view of a section of the flexible polymer sheet of the sampling module of  FIG. 78  illustrating the flexible conductors and contact points deposited on the bottom surface of the flexible polymer sheet. 
         FIG. 80  is a perspective view of the body portion of the sampling module of  FIG. 77  without the flexible polymer cover sheet or lancet. 
         FIG. 81  is an enlarged portion of the body portion of the sampling module of  FIG. 80  illustrating the input port, sample flow channel, analytical region, lancet channel and lancet guides of the sampling module. 
         FIG. 82  is an enlarged elevational view of a portion of an alternative embodiment of a sampling module having a plurality of small volume analytical regions. 
         FIG. 83  is a perspective view of a body portion of a lancet module that can house and guide a lancet without sampling or analytical functions. 
         FIG. 84  is an elevational view of a drive coupler having a T-slot configured to accept a drive head of a lancet. 
         FIG. 85  is an elevational view of the drive coupler of  FIG. 84  from the side and illustrating the guide ramps of the drive coupler. 
         FIG. 86  is a perspective view of the drive coupler of  FIG. 84  with a lancet being loaded into the T-slot of the drive coupler. 
         FIG. 87  is a perspective view of the drive coupler of  FIG. 86  with the drive head of the lancet completely loaded into the T-slot of the drive coupler. 
         FIG. 88  is a perspective view of a sampling module belt disposed within the T-slot of the drive coupler with a drive head of a lancet of one of the sampling modules loaded within the T-slot of the drive coupler. 
         FIG. 89  is a perspective view of a sampling module cartridge with the sampling modules arranged in a ring configuration. 
         FIG. 90  is a perspective view of a sampling module cartridge with the plurality of sampling modules arranged in a block matrix with lancet drive heads configured to mate with a drive coupler having adhesive coupling. 
         FIG. 91  is a side view of an alternative embodiment of a drive coupler having a lateral slot configured to accept the L-shaped drive head of the lancet that is disposed within a lancet module and shown with the L-shaped drive head loaded in the lateral slot. 
         FIG. 92  is an exploded view of the drive coupler, lancet with L-shaped drive head and lancet module of  FIG. 91 . 
         FIG. 93  is a perspective view of the front of a lancet cartridge coupled to the distal end of a controlled electromagnetic driver. 
         FIG. 94  is an elevational front view of the lancet cartridge of  FIG. 93 . 
         FIG. 95  is a top view of the lancet cartridge of  FIG. 93 . 
         FIG. 96  is a perspective view of the lancet cartridge of  FIG. 93  with a portion of the cartridge body and lancet receptacle not shown for purposes of illustration of the internal mechanism. 
         FIGS. 97-101  illustrate an embodiment of an agent injection device. 
         FIGS. 102-106  illustrate an embodiment of a cartridge for use in sampling having a sampling cartridge body and a lancet cartridge body. 
     
    
    
     DETAILED DESCRIPTION 
     Variations in skin thickness including the stratum corneum and hydration of the epidermis can yield different results between different users with existing tissue penetration devices, such as lancing devices wherein the tissue penetrating element of the tissue penetration device is a lancet. Many current devices rely on adjustable mechanical stops or damping, to control the lancet&#39;s depth of penetration. 
     Displacement velocity profiles for both spring driven and cam driven tissue penetration devices are shown in  FIGS. 1 and 2 , respectively. Velocity is plotted against displacement X of the lancet.  FIG. 1  represents a displacement/velocity profile typical of spring driven devices. The lancet exit velocity increases until the lancet hits the surface of the skin  10 . Because of the tensile characteristics of the skin, it will bend or deform until the lancet tip cuts the surface  20 , the lancet will then penetrate the skin until it reaches a full stop  30 . At this point displacement is maximal and reaches a limit of penetration and the lancet stops. Mechanical stops absorb excess energy from the driver and transfer it to the lancet. The energy stored in the spring can cause recoil resulting in multiple piercing as seen by the coiled profile in  FIG. 1 . This results in unnecessary pain from the additional tissue penetration as well as from transferring vibratory energy into the skin and exciting nerve endings. Retraction of the lancet then occurs and the lancet exits the skin  40  to return into the housing. Velocity cannot be controlled in any meaningful way for this type of spring-powered driver. 
       FIG. 2  shows a displacement/velocity profile for a cam driven driver, which is similar to that of  FIG. 1 , but because the return path is specified in the cam configuration, there is no possibility of multiple tissue penetrations from one actuation. Cam based drivers can offer some level of control of lancet velocity vs. displacement, but not enough to achieve many desirable displacement/velocity profiles. 
     Advantages are achieved by utilizing a controllable force driver to drive a lancet, such as a driver, powered by electromagnetic energy. A controllable driver can achieve a desired velocity versus position profile, such as that shown in  FIG. 3 . Embodiments of the present invention allow for the ability to accurately control depth of penetration, to control lancet penetration and withdrawal velocity, and therefore reduce the pain perceived when cutting into the skin. Embodiments of the invention include a controllable driver that can be used with a feedback loop with a position sensor to control the power delivered to the lancet, which can optimize the velocity and displacement profile to compensate for variations in skin thickness 
     Pain reduction can be achieved by using a rapid lancet cutting speed, which is facilitated by the use of a lightweight lancet. The rapid cutting minimizes the shock waves produced when the lancet strikes the skin in addition to compressing the skin for efficient cutting. If a controllable driver is used, the need for a mechanical stop can be eliminated. Due to the very light mass of the lancet and lack of a mechanical stop, there is little or no vibrational energy transferred to the finger during cutting. 
     The lancing devices such as those whose velocity versus position profiles are shown in  FIGS. 1 and 2  typically yield 50% spontaneous blood. In addition, some lancing events are unsuccessful and yield no blood, even on milking the finger. A spontaneous blood droplet generation is dependent on reaching the blood capillaries and venuoles, which yield the blood sample. It is therefore an issue of correct depth of penetration of the cutting device. Due to variations in skin thickness and hydration, some types of skin will deform more before cutting starts, and hence the actual depth of penetration will be less, resulting in less capillaries and venuoles cut. A controllable force driver can control the depth of penetration of a lancet and hence improve the spontaneity of blood yield. Furthermore, the use of a controllable force driver can allow for slow retraction of the lancet (slower than the cutting velocity) resulting in improved success rate due to the would channel remaining open for the free passage of blood to the surface of the skin. 
     Spontaneous blood yield occurs when blood from the cut vessels flow up the wound tract to the surface of the skin, where it can be collected and tested. Tissue elasticity parameters may force the wound tract to close behind the retracting lancet preventing the blood from reaching the surface. If however, the lancet were to be withdrawn slowly from the wound tract, thus keeping the wound open, blood could flow up the patent channel behind the tip of the lancet as it is being withdrawn (ref.  FIGS. 10 and 11 ). Hence the ability to control the lancet speed into and out of the wound allows the device to compensate for changes in skin thickness and variations in skin hydration and thereby achieves spontaneous blood yield with maximum success rate while minimizing pain. 
     An electromagnetic driver can be coupled directly to the lancet minimizing the mass of the lancet and allowing the driver to bring the lancet to a stop at a predetermined depth without the use of a mechanical stop. Alternatively, if a mechanical stop is required for positive positioning, the energy transferred to the stop can be minimized. The electromagnetic driver allows programmable control over the velocity vs. position profile of the entire lancing process including timing the start of the lancet, tracking the lancet position, measuring the lancet velocity, controlling the distal stop acceleration, and controlling the skin penetration depth. 
     Referring to  FIG. 4 , an embodiment of a tissue penetration device is shown. The tissue penetration device includes a controllable force driver in the form of an electromagnetic driver, which can be used to drive a lancet. The term Lancet, as used herein, generally includes any sharp or blunt member, preferably having a relatively low mass, used to puncture the skin for the purpose of cutting blood vessels and allowing blood to flow to the surface of the skin. The term Electromagnetic driver, as used herein, generally includes any device that moves or drives a tissue penetrating element, such as a lancet under an electrically or magnetically induced force.  FIG. 4  is a partially exploded view of an embodiment of an electromagnetic driver. The top half of the driver is shown assembled. The bottom half of the driver is shown exploded for illustrative purposes. 
       FIG. 4  shows the inner insulating housing  22  separated from the stationary housing or PC board  20 , and the lancet  24  and flag  26  assembly separated from the inner insulating housing  22  for illustrative purposes. In addition, only four rivets  18  are shown as attached to the inner insulating housing  22  and separated from the PC board  20 . In an embodiment, each coil drive field core in the PC board located in the PC Board  20  and  30  is connected to the inner insulating housing  22  and  32  with rivets. 
     The electromagnetic driver has a moving part comprising a lancet assembly with a lancet  24  and a magnetically permeable flag  26  attached at the proximal or drive end and a stationary part comprising a stationary housing assembly with electric field coils arranged so that they produce a balanced field at the flag to reduce or eliminate any net lateral force on the flag. The electric field coils are generally one or more metal coils, which generate a magnetic field when electric current passes through the coil. The iron flag is a flat or enlarged piece of magnetic material, which increases the surface area of the lancet assembly to enhance the magnetic forces generated between the proximal end of the lancet and a magnetic field produced by the field coils. The combined mass of the lancet and the iron flag can be minimized to facilitate rapid acceleration for introduction into the skin of a patient, to reduce the impact when the lancet stops in the skin, and to facilitate prompt velocity profile changes throughout the sampling cycle. 
     The stationary housing assembly consists of a PC board  20 , a lower inner insulating housing  22 , an upper inner insulating housing  32 , an upper PC board  30 , and rivets  18  assembled into a single unit. The lower and upper inner insulating housing  22  and  32  are relieved to form a slot so that lancet assembly can be slid into the driver assembly from the side perpendicular to the direction of the lancet&#39;s advancement and retraction. This allows the disposal of the lancet assembly and reuse of the stationary housing assembly with another lancet assembly while avoiding accidental lancet launches during replacement. 
     The electric field coils in the upper and lower stationary housing  20  and  30  are fabricated in a multi-layer printed circuit (PC) board. They may also be conventionally wound wire coils. A Teflon® material, or other low friction insulating material is used to construct the lower and upper inner insulating housing  22  and  32 . Each insulating housing is mounted on the PC board to provide electrical insulation and physical protection, as well as to provide a low-friction guide for the lancet. The lower and upper inner insulating housing  22  and  32  provide a reference surface with a small gap so that the lancet assembly  24  and  26  can align with the drive field coils in the PC board for good magnetic coupling. 
     Rivets  18  connect the lower inner insulating housing  22  to the lower stationary housing  20  and are made of magnetically permeable material such as ferrite or steel, which serves to concentrate the magnetic field. This mirrors the construction of the upper inner insulating housing  32  and upper stationary housing  30 . These rivets form the poles of the electric field coils. The PC board is fabricated with multiple layers of coils or with multiple boards. Each layer supports spiral traces around a central hole. Alternate layers spiral from the center outwards or from the edges inward. In this way each layer connects via simple feed-through holes, and the current always travels in the same direction, summing the ampere-turns. 
     The PC boards within the lower and upper stationary housings  20  and  30  are connected to the lower and upper inner insulating housings  22  and  32  with the rivets  18 . The lower and upper inner insulating housings  22  and  32  expose the rivet heads on opposite ends of the slot where the lancet assembly  24  and  26  travels. The magnetic field lines from each rivet create magnetic poles at the rivet heads. An iron bar on the opposite side of the PC board within each of the lower and upper stationary housing  20  and  30  completes the magnetic circuit by connecting the rivets. Any fastener made of magnetically permeable material such as iron or steel can be used In place of the rivets. A single component made of magnetically permeable material and formed in a horseshoe shape can be used in place of the rivet/screw and iron bar assembly. In operation, the magnetically permeable flag  26  attached to the lancet  24  is divided into slits and bars  34 . The slit patterns are staggered so that coils can drive the flag  26  in two, three or more phases. 
     Both lower and upper PC boards  20  and  30  contain drive coils so that there is a symmetrical magnetic field above and below the flag  26 . When the pair of PC boards is turned on, a magnetic field is established around the bars between the slits of the magnetically permeable iron on the flag  26 . The bars of the flag experience a force that tends to move the magnetically permeable material to a position minimizing the number and length of magnetic field lines and conducting the magnetic field lines between the magnetic poles. 
     When a bar of the flag  26  is centered between the rivets  18  of a magnetic pole, there is no net force on the flag, and any disturbing force is resisted by imbalance in the field. This embodiment of the device operates on a principle similar to that of a solenoid. Solenoids cannot push by repelling iron; they can only pull by attracting the iron into a minimum energy position. The slits  34  on one side of the flag  26  are offset with respect to the other side by approximately one half of the pitch of the poles. By alternately activating the coils on each side of the PC board, the lancet assembly can be moved with respect to the stationary housing assembly. The direction of travel is established by selectively energizing the coils adjacent the metal flag on the lancet assembly. Alternatively, a three phase, three-pole design or a shading coil that is offset by one-quarter pitch establishes the direction of travel. The lower and upper PC boards  20  and  30  shown in  FIG. 4  contain electric field coils, which drive the lancet assembly and the circuitry for controlling the entire electromagnetic driver. 
     The embodiment described above generally uses the principles of a magnetic attraction drive, similar to commonly available circular stepper motors (Hurst Manufacturing BA Series motor, or “Electrical Engineering Handbook” Second edition p 1472-1474, 1997). These references are hereby incorporated by reference. Other embodiments can include a linear induction drive that uses a changing magnetic field to induce electric currents in the lancet assembly. These induced currents produce a secondary magnetic field that repels the primary field and applies a net force on the lancet assembly. The linear induction drive uses an electrical drive control that sweeps a magnetic field from pole to pole, propelling the lancet before it. Varying the rate of the sweep and the magnitude of the field by altering the driving voltage and frequency controls the force applied to the lancet assembly and its velocity. 
     The arrangement of the coils and rivets to concentrate the magnetic flux also applies to the induction design creating a growing magnetic field as the electric current in the field switches on. This growing magnetic field creates an opposing electric current in the conductive flag. In a linear induction motor the flag is electrically conductive, and its magnetic properties are unimportant. Copper or aluminum are materials that can be used for the conductive flags. Copper is generally used because of its good electrical conductivity. The opposing electrical field produces an opposing magnetic field that repels the field of the coils. By phasing the power of the coils, a moving field can be generated which pushes the flag along just below the synchronous speed of the coils. By controlling the rate of sweep, and by generating multiple sweeps, the flag can be moved at a desired speed. 
       FIG. 5  shows another embodiment of a solenoid type electromagnetic driver that is capable of driving an iron core or slug mounted to the lancet assembly using a direct current (DC) power supply. The electromagnetic driver includes a driver coil pack that is divided into three separate coils along the path of the lancet, two end coils and a middle coil. Direct current is alternated to the coils to advance and retract the lancet. Although the driver coil pack is shown with three coils, any suitable number of coils may be used, for example, 4, 5, 6, 7 or more coils may be used. 
     The stationary iron housing  40  contains the driver coil pack with a first coil  52  is flanked by iron spacers  50  which concentrate the magnetic flux at the inner diameter creating magnetic poles. The inner insulating housing  48  isolates the lancet  42  and iron core  46  from the coils and provides a smooth, low friction guide surface. The lancet guide  44  further centers the lancet  42  and iron core  46 . The lancet  42  is protracted and retracted by alternating the current between the first coil  52 , the middle coil, and the third coil to attract the iron core  46 . Reversing the coil sequence and attracting the core and lancet back into the housing retracts the lancet. The lancet guide  44  also serves as a stop for the iron core  46  mounted to the lancet  42 . 
     As discussed above, tissue penetration devices which employ spring or cam driving methods have a symmetrical or nearly symmetrical actuation displacement and velocity profiles on the advancement and retraction of the lancet as shown in  FIGS. 6 and 7 . In most of the available lancet devices, once the launch is initiated, the stored energy determines the velocity profile until the energy is dissipated. Controlling impact, retraction velocity, and dwell time of the lancet within the tissue can be useful in order to achieve a high success rate while accommodating variations in skin properties and minimize pain. Advantages can be achieved by taking into account that tissue dwell time is related to the amount of skin deformation as the lancet tries to puncture the surface of the skin and variance in skin deformation from patient to patient based on skin hydration. 
     The ability to control velocity and depth of penetration can be achieved by use of a controllable force driver where feedback is an integral part of driver control. Such drivers can control either metal or polymeric lancets or any other type of tissue penetration element. The dynamic control of such a driver is illustrated in  FIG. 8  which illustrates an embodiment of a controlled displacement profile and  FIG. 9  which illustrates an embodiment of a the controlled velocity profile. These are compared to  FIGS. 6 and 7 , which illustrate embodiments of displacement and velocity profiles, respectively, of a harmonic spring/mass powered driver. 
     Reduced pain can be achieved by using impact velocities of greater than 2 m/s entry of a tissue penetrating element, such as a lancet, into tissue. 
     Retraction of the lancet at a low velocity following the sectioning of the venuole/capillary mesh allows the blood to flood the wound tract and flow freely to the surface, thus using the lancet to keep the channel open during retraction as shown in  FIGS. 10 and 11 . Low-velocity retraction of the lancet near the wound flap prevents the wound flap from sealing off the channel. Thus, the ability to slow the lancet retraction directly contributes to increasing the success rate of obtaining blood. Increasing the sampling success rate to near 100% can be important to the combination of sampling and acquisition into an integrated sampling module such as an integrated glucose-sampling module, which incorporates a glucose test strip. 
     Referring again to  FIG. 5 , the lancet and lancet driver are configured so that feedback control is based on lancet displacement, velocity, or acceleration. The feedback control information relating to the actual lancet path is returned to a processor such as that illustrated in  FIG. 12  that regulates the energy to the driver, thereby precisely controlling the lancet throughout its advancement and retraction. The driver may be driven by electric current, which includes direct current and alternating current. 
     In  FIG. 5 , the electromagnetic driver shown is capable of driving an iron core or slug mounted to the lancet assembly using a direct current (DC) power supply and is also capable of determining the position of the iron core by measuring magnetic coupling between the core and the coils. The coils can be used in pairs to draw the iron core into the driver coil pack. As one of the coils is switched on, the corresponding induced current in the adjacent coil can be monitored. The strength of this induced current is related to the degree of magnetic coupling provided by the iron core, and can be used to infer the position of the core and hence, the relative position of the lancet. 
     After a period of time, the drive voltage can be turned off, allowing the coils to relax, and then the cycle is repeated. The degree of magnetic coupling between the coils is converted electronically to a proportional DC voltage that is supplied to an analog-to-digital converter. The digitized position signal is then processed and compared to a desired “nominal” position by a central processing unit (CPU). The CPU to set the level and/or length of the next power pulse to the solenoid coils uses error between the actual and nominal positions. 
     In another embodiment, the driver coil pack has three coils consisting of a central driving coil flanked by balanced detection coils built into the driver assembly so that they surround an actuation or magnetically active region with the region centered on the middle coil at mid-stroke. When a current pulse is applied to the central coil, voltages are induced in the adjacent sense coils. If the sense coils are connected together so that their induced voltages oppose each other, the resulting signal will be positive for deflection from mid-stroke in one direction, negative in the other direction, and zero at mid-stroke. This measuring technique is commonly used in Linear Variable Differential Transformers (LVDT). Lancet position is determined by measuring the electrical balance between the two sensing coils. 
     In another embodiment, a feedback loop can use a commercially available LED/photo transducer module such as the OPB703 manufactured by Optek Technology, Inc., 1215 W. Crosby Road, Carrollton, Tex., 75006 to determine the distance from the fixed module on the stationary housing to a reflective surface or target mounted on the lancet assembly. The LED acts as a light emitter to send light beams to the reflective surface, which in turn reflects the light back to the photo transducer, which acts as a light sensor. Distances over the range of 4 mm or so are determined by measuring the intensity of the reflected light by the photo transducer. In another embodiment, a feedback loop can use a magnetically permeable region on the lancet shaft itself as the core of a Linear Variable Differential Transformer (LVDT). 
     A permeable region created by selectively annealing a portion of the lancet shaft, or by including a component in the lancet assembly, such as ferrite, with sufficient magnetic permeability to allow coupling between adjacent sensing coils. Coil size, number of windings, drive current, signal amplification, and air gap to the permeable region are specified in the design process. In another embodiment, the feedback control supplies a piezoelectric driver, superimposing a high frequency oscillation on the basic displacement profile. The piezoelectric driver provides improved cutting efficiency and reduces pain by allowing the lancet to “saw” its way into the tissue or to destroy cells with cavitation energy generated by the high frequency of vibration of the advancing edge of the lancet. The drive power to the piezoelectric driver is monitored for an impedance shift as the device interacts with the target tissue. The resulting force measurement, coupled with the known mass of the lancet is used to determine lancet acceleration, velocity, and position. 
       FIG. 12  illustrates the operation of a feedback loop using a processor. The processor  60  stores profiles  62  in non-volatile memory. A user inputs information  64  about the desired circumstances or parameters for a lancing event. The processor  60  selects a driver profile  62  from a set of alternative driver profiles that have been preprogrammed in the processor  60  based on typical or desired tissue penetration device performance determined through testing at the factory or as programmed in by the operator. The processor  60  may customize by either scaling or modifying the profile based on additional user input information  64 . Once the processor has chosen and customized the profile, the processor  60  is ready to modulate the power from the power supply  66  to the lancet driver  68  through an amplifier  70 . The processor  60  measures the location of the lancet  72  using a position sensing mechanism  74  through an analog to digital converter  76 . Examples of position sensing mechanisms have been described in the embodiments above. The processor  60  calculates the movement of the lancet by comparing the actual profile of the lancet to the predetermined profile. The processor  60  modulates the power to the lancet driver  68  through a signal generator  78 , which controls the amplifier  70  so that the actual profile of the lancet does not exceed the predetermined profile by more than a preset error limit. The error limit is the accuracy in the control of the lancet. 
     After the lancing event, the processor  60  can allow the user to rank the results of the lancing event. The processor  60  stores these results and constructs a database  80  for the individual user. Using the database  80 , the processor  60  calculates the profile traits such as degree of painlessness, success rate, and blood volume for various profiles  62  depending on user input information  64  to optimize the profile to the individual user for subsequent lancing cycles. These profile traits depend on the characteristic phases of lancet advancement and retraction. The processor  60  uses these calculations to optimize profiles  62  for each user. In addition to user input information  64 , an internal clock allows storage in the database  80  of information such as the time of day to generate a time stamp for the lancing event and the time between lancing events to anticipate the user&#39;s diurnal needs. The database stores information and statistics for each user and each profile that particular user uses. 
     In addition to varying the profiles, the processor  60  can be used to calculate the appropriate lancet diameter and geometry necessary to realize the blood volume required by the user. For example, if the user requires a 1-5 micro liter volume of blood, the processor selects a 200 micron diameter lancet to achieve these results. For each class of lancet, both diameter and lancet tip geometry, is stored in the processor to correspond with upper and lower limits of attainable blood volume based on the predetermined displacement and velocity profiles. 
     The lancing device is capable of prompting the user for information at the beginning and the end of the lancing event to more adequately suit the user. The goal is to either change to a different profile or modify an existing profile. Once the profile is set, the force driving the lancet is varied during advancement and retraction to follow the profile. The method of lancing using the lancing device comprises selecting a profile, lancing according to the selected profile, determining lancing profile traits for each characteristic phase of the lancing cycle, and optimizing profile traits for subsequent lancing events. 
       FIG. 13  shows an embodiment of the characteristic phases of lancet advancement and retraction on a graph of force versus time illustrating the force exerted by the lancet driver on the lancet to achieve the desired displacement and velocity profile. The characteristic phases are the lancet introduction phase A-C where the lancet is longitudinally advanced into the skin, the lancet rest phase D where the lancet terminates its longitudinal movement reaching its maximum depth and becoming relatively stationary, and the lancet retraction phase E-G where the lancet is longitudinally retracted out of the skin. The duration of the lancet retraction phase E-G is longer than the duration of the lancet introduction phase A-C, which in turn is longer than the duration of the lancet rest phase D. 
     The introduction phase further comprises a lancet launch phase prior to A when the lancet is longitudinally moving through air toward the skin, a tissue contact phase at the beginning of A when the distal end of the lancet makes initial contact with the skin, a tissue deformation phase A when the skin bends depending on its elastic properties which are related to hydration and thickness, a tissue lancing phase which comprises when the lancet hits the inflection point on the skin and begins to cut the skin B and the lancet continues cutting the skin C. The lancet rest phase D is the limit of the penetration of the lancet into the skin. Pain is reduced by minimizing the duration of the lancet introduction phase A-C so that there is a fast incision to a certain penetration depth regardless of the duration of the deformation phase A and inflection point cutting B which will vary from user to user. Success rate is increased by measuring the exact depth of penetration from inflection point B to the limit of penetration in the lancet rest phase D. This measurement allows the lancet to always, or at least reliably, hit the capillary beds which are a known distance underneath the surface of the skin. 
     The lancet retraction phase further comprises a primary retraction phase E when the skin pushes the lancet out of the wound tract, a secondary retraction phase F when the lancet starts to become dislodged and pulls in the opposite direction of the skin, and lancet exit phase G when the lancet becomes free of the skin. Primary retraction is the result of exerting a decreasing force to pull the lancet out of the skin as the lancet pulls away from the finger. Secondary retraction is the result of exerting a force in the opposite direction to dislodge the lancet. Control is necessary to keep the wound tract open as blood flows up the wound tract. Blood volume is increased by using a uniform velocity to retract the lancet during the lancet retraction phase E-G regardless of the force required for the primary retraction phase E or secondary retraction phase F, either of which may vary from user to user depending on the properties of the user&#39;s skin. 
       FIG. 14  shows a standard industry lancet for glucose testing which has a three-facet geometry. Taking a rod of diameter  114  and grinding 8 degrees to the plane of the primary axis to create the primary facet  110  produces the lancet  116 . The secondary facets  112  are then created by rotating the shaft of the needle 15 degrees, and then rolling over 12 degrees to the plane of the primary facet. Other possible geometry&#39;s require altering the lancet&#39;s production parameters such as shaft diameter, angles, and translation distance. 
       FIG. 15  illustrates facet and tip geometry  120  and  122 , diameter  124 , and depth  126  which are significant factors in reducing pain, blood volume and success rate. It is known that additional cutting by the lancet is achieved by increasing the shear percentage or ratio of the primary to secondary facets, which when combined with reducing the lancet&#39;s diameter reduces skin tear and penetration force and gives the perception of less pain. Overall success rate of blood yield, however, also depends on a variety of factors, including the existence of facets, facet geometry, and skin anatomy. 
       FIG. 16  shows another embodiment of displacement versus time profile of a lancet for a controlled lancet retraction.  FIG. 17  shows the velocity vs. time profile of the lancet for the controlled retraction of  FIG. 16 . The lancet driver controls lancet displacement and velocity at several steps in the lancing cycle, including when the lancet cuts the blood vessels to allow blood to pool  130 , and as the lancet retracts, regulating the retraction rate to allow the blood to flood the wound tract while keeping the wound flap from sealing the channel  132  to permit blood to exit the wound. 
     In addition to slow retraction of a tissue-penetrating element in order to hold the wound open to allow blood to escape to the skin surface, other methods are contemplated.  FIG. 18  shows the use of an embodiment of the invention, which includes a retractable coil on the lancet tip. A coiled helix or tube  140  is attached externally to lancet  116  with the freedom to slide such that when the lancet penetrates the skin  150 , the helix or tube  140  follows the trajectory of the lancet  116 . The helix begins the lancing cycle coiled around the facets and shaft of the lancet  144 . As the lancet penetrates the skin, the helix braces the wound tract around the lancet  146 . As the lancet retracts, the helix remains to brace open the wound tract, keeping the wound tract from collapsing and keeping the surface skin flap from closing  148 . This allows blood  152  to pool and flow up the channel to the surface of the skin. The helix is then retracted as the lancet pulls the helix to the point where the helix is decompressed to the point where the diameter of the helix becomes less than the diameter of the wound tract and becomes dislodged from the skin. 
     The tube or helix  140  is made of wire or metal of the type commonly used in angioplasty stents such as stainless steel, nickel titanium alloy or the like. Alternatively the tube or helix  140  or a ring can be made of a biodegradable material, which braces the wound tract by becoming lodged in the skin. Biodegradation is completed within seconds or minutes of insertion, allowing adequate time for blood to pool and flow up the wound tract. Biodegradation is activated by heat, moisture, or pH from the skin. 
     Alternatively, the wound could be held open by coating the lancet with a powder or other granular substance. The powder coats the wound tract and keeps it open when the lancet is withdrawn. The powder or other granular substance can be a coarse bed of microspheres or capsules which hold the channel open while allowing blood to flow through the porous interstices. 
     In another embodiment the wound can be held open using a two-part needle, the outer part in the shape of a “U” and the inner part filling the “U.” After creating the wound the inner needle is withdrawn leaving an open channel, rather like the plugs that are commonly used for withdrawing sap from maple trees. 
       FIG. 19  shows a further embodiment of a method and device for facilitating blood flow utilizing an elastomer to coat the wound. This method uses an elastomer  154 , such as silicon rubber, to coat or brace the wound tract  156  by covering and stretching the surface of the finger  158 . The elastomer  154  is applied to the finger  158  prior to lancing. After a short delay, the lancet (not shown) then penetrates the elastomer  154  and the skin on the surface of the finger  158  as is seen in  160 . Blood is allowed to pool and rise to the surface while the elastomer  154  braces the wound tract  156  as is seen in  162  and  164 . Other known mechanisms for increasing the success rate of blood yield after lancing can include creating a vacuum, suctioning the wound, applying an adhesive strip, vibration while cutting, or initiating a second lance if the first is unsuccessful. 
       FIG. 20  illustrates an embodiment of a tissue penetration device, more specifically, a lancing device  180  that includes a controllable driver  179  coupled to a tissue penetration element. The lancing device  180  has a proximal end  181  and a distal end  182 . At the distal end  182  is the tissue penetration element in the form of a lancet  183 , which is coupled to an elongate coupler shaft  184  by a drive coupler  185 . The elongate coupler shaft  184  has a proximal end  186  and a distal end  187 . A driver coil pack  188  is disposed about the elongate coupler shaft  184  proximal of the lancet  183 . A position sensor  191  is disposed about a proximal portion  192  of the elongate coupler shaft  184  and an electrical conductor  194  electrically couples a processor  193  to the position sensor  191 . The elongate coupler shaft  184  driven by the driver coil pack  188  controlled by the position sensor  191  and processor  193  form the controllable driver, specifically, a controllable electromagnetic driver. 
     Referring to  FIG. 21 , the lancing device  180  can be seen in more detail, in partial longitudinal section. The lancet  183  has a proximal end  195  and a distal end  196  with a sharpened point at the distal end  196  of the lancet  183  and a drive head  198  disposed at the proximal end  195  of the lancet  183 . A lancet shaft  201  is disposed between the drive head  198  and the sharpened point  197 . The lancet shaft  201  may be comprised of stainless steel, or any other suitable material or alloy and have a transverse dimension of about 0.1 to about 0.4 mm. The lancet shaft may have a length of about 3 mm to about 50 mm, specifically, about 15 mm to about 20 mm. The drive head  198  of the lancet  183  is an enlarged portion having a transverse dimension greater than a transverse dimension of the lancet shaft  201  distal of the drive head  198 . This configuration allows the drive head  198  to be mechanically captured by the drive coupler  185 . The drive head  198  may have a transverse dimension of about 0.5 to about 2 mm. 
     A magnetic member  202  is secured to the elongate coupler shaft  184  proximal of the drive coupler  185  on a distal portion  203  of the elongate coupler shaft  184 . The magnetic member  202  is a substantially cylindrical piece of magnetic material having an axial lumen  204  extending the length of the magnetic member  202 . The magnetic member  202  has an outer transverse dimension that allows the magnetic member  202  to slide easily within an axial lumen  205  of a low friction, possibly lubricious, polymer guide tube  205 ′ disposed within the driver coil pack  188 . The magnetic member  202  may have an outer transverse dimension of about 1.0 to about 5.0 mm, specifically, about 2.3 to about 2.5 mm. The magnetic member  202  may have a length of about 3.0 to about 5.0 mm, specifically, about 4.7 to about 4.9 mm. The magnetic member  202  can be made from a variety of magnetic materials including ferrous metals such as ferrous steel, iron, ferrite, or the like. The magnetic member  202  may be secured to the distal portion  203  of the elongate coupler shaft  184  by a variety of methods including adhesive or epoxy bonding, welding, crimping or any other suitable method. 
     Proximal of the magnetic member  202 , an optical encoder flag  206  is secured to the elongate coupler shaft  184 . The optical encoder flag  206  is configured to move within a slot  207  in the position sensor  191 . The slot  207  of the position sensor  191  is formed between a first body portion  208  and a second body portion  209  of the position sensor  191 . The slot  207  may have separation width of about 1.5 to about 2.0 mm. The optical encoder flag  206  can have a length of about 14 to about 18 mm, a width of about 3 to about 5 mm and a thickness of about 0.04 to about 0.06 mm. 
     The optical encoder flag  206  interacts with various optical beams generated by LEDs disposed on or in the position sensor body portions  208  and  209  in a predetermined manner. The interaction of the optical beams generated by the LEDs of the position sensor  191  generates a signal that indicates the longitudinal position of the optical flag  206  relative to the position sensor  191  with a substantially high degree of resolution. The resolution of the position sensor  191  may be about 200 to about 400 cycles per inch, specifically, about 350 to about 370 cycles per inch. The position sensor  191  may have a speed response time (position/time resolution) of 0 to about 120,000 Hz, where one dark and light stripe of the flag constitutes one Hertz, or cycle per second. The position of the optical encoder flag  206  relative to the magnetic member  202 , driver coil pack  188  and position sensor  191  is such that the optical encoder  191  can provide precise positional information about the lancet  183  over the entire length of the lancet&#39;s power stroke. 
     An optical encoder that is suitable for the position sensor  191  is a linear optical incremental encoder, model HEDS 9200, manufactured by Agilent Technologies. The model HEDS 9200 may have a length of about 20 to about 30 mm, a width of about 8 to about 12 mm, and a height of about 9 to about 11 mm. Although the position sensor  191  illustrated is a linear optical incremental encoder, other suitable position sensor embodiments could be used, provided they posses the requisite positional resolution and time response. The HEDS 9200 is a two channel device where the channels are 90 degrees out of phase with each other. This results in a resolution of four times the basic cycle of the flag. These quadrature outputs make it possible for the processor to determine the direction of lancet travel. Other suitable position sensors include capacitive encoders, analog reflective sensors, such as the reflective position sensor discussed above, and the like. 
     A coupler shaft guide  211  is disposed towards the proximal end  181  of the lancing device  180 . The guide  211  has a guide lumen  212  disposed in the guide  211  to slidingly accept the proximal portion  192  of the elongate coupler shaft  184 . The guide  211  keeps the elongate coupler shaft  184  centered horizontally and vertically in the slot  202  of the optical encoder  191 . 
     The driver coil pack  188 , position sensor  191  and coupler shaft guide  211  are all secured to a base  213 . The base  213  is longitudinally coextensive with the driver coil pack  188 , position sensor  191  and coupler shaft guide  211 . The base  213  can take the form of a rectangular piece of metal or polymer, or may be a more elaborate housing with recesses, which are configured to accept the various components of the lancing device  180 . 
     As discussed above, the magnetic member  202  is configured to slide within an axial lumen  205  of the driver coil pack  188 . The driver coil pack  188  includes a most distal first coil  214 , a second coil  215 , which is axially disposed between the first coil  214  and a third coil  216 , and a proximal-most fourth coil  217 . Each of the first coil  214 , second coil  215 , third coil  216  and fourth coil  217  has an axial lumen. The axial lumens of the first through fourth coils are configured to be coaxial with the axial lumens of the other coils and together form the axial lumen  205  of the driver coil pack  188  as a whole. Axially adjacent each of the coils  214 - 217  is a magnetic disk or washer  218  that augments completion of the magnetic circuit of the coils  214 - 217  during a lancing cycle of the device  180 . The magnetic washers  218  of the embodiment of  FIG. 21  are made of ferrous steel but could be made of any other suitable magnetic material, such as iron or ferrite. The outer shell  189  of the driver coil pack  188  is also made of iron or steel to complete the magnetic path around the coils and between the washers  218 . The magnetic washers  218  have an outer diameter commensurate with an outer diameter of the driver coil pack  188  of about 4.0 to about 8.0 mm. The magnetic washers  218  have an axial thickness of about 0.05, to about 0.4 mm, specifically, about 0.15 to about 0.25 mm. 
     Wrapping or winding an elongate electrical conductor  221  about an axial lumen until a sufficient number of windings have been achieved forms the coils  214 - 217 . The elongate electrical conductor  221  is generally an insulated solid copper wire with a small outer transverse dimension of about 0.06 mm to about 0.88 mm, specifically, about 0.3 mm to about 0.5 mm. In one embodiment, 32 gauge copper wire is used for the coils  214 - 217 . The number of windings for each of the coils  214 - 217  of the driver pack  188  may vary with the size of the coil, but for some embodiments each coil  214 - 217  may have about 30 to about 80 turns, specifically, about 50 to about 60 turns. Each coil  214 - 217  can have an axial length of about 1.0 to about 3.0 mm, specifically, about 1.8 to about 2.0 mm. Each coil  214 - 217  can have an outer transverse dimension or diameter of about 4.0, to about 2.0 mm, specifically, about 9.0 to about 12.0 mm. The axial lumen  205  can have a transverse dimension of about 1.0 to about 3.0 mm. 
     It may be advantageous in some driver coil  188  embodiments to replace one or more of the coils with permanent magnets, which produce a magnetic field similar to that of the coils when the coils are activated. In particular, it may be desirable in some embodiments to replace the second coil  215 , the third coil  216  or both with permanent magnets. In addition, it may be advantageous to position a permanent magnet at or near the proximal end of the coil driver pack in order to provide fixed magnet zeroing function for the magnetic member (Adams magnetic Products 23A0002 flexible magnet material (800) 747-7543)). 
       FIGS. 20 and 21  show a permanent bar magnet  219  disposed on the proximal end of the driver coil pack  188 . As shown in  FIG. 21 , the bar magnet  219  is arranged so as to have one end disposed adjacent the travel path of the magnetic member  202  and has a polarity configured so as to attract the magnetic member  202  in a centered position with respect to the bar magnet  219 . Note that the polymer guide tube  205 ′ can be configured to extend proximally to insulate the inward radial surface of the bar magnet  219  from an outer surface of the magnetic member  202 . This arrangement allows the magnetic member  219  and thus the elongate coupler shaft  184  to be attracted to and held in a zero point or rest position without the consumption of electrical energy from the power supply  225 . 
     Having a fixed zero or start point for the elongate coupler shaft  184  and lancet  183  can be critical to properly controlling the depth of penetration of the lancet  183  as well as other lancing parameters. This can be because some methods of depth penetration control for a controllable driver measure the acceleration and displacement of the elongate coupler shaft  184  and lancet  183  from a known start position. If the distance of the lancet tip  196  from the target tissue is known, acceleration and displacement of the lancet is known and the start position of the lancet is know, the time and position of tissue contact and depth of penetration can be determined by the processor  193 . 
     Any number of configurations for a magnetic bar  219  can be used for the purposes discussed above. In particular, a second permanent bar magnet (not shown) could be added to the proximal end of the driver coil pack  188  with the magnetic fields of the two bar magnets configured to complement each other. In addition, a disc magnet  219 ′ could be used as illustrated in  FIG. 22 . Disc magnet  219 ′ is shown disposed at the proximal end of the driver coiled pack  188  with a polymer non-magnetic disc  219 ″ disposed between the proximal-most coil  217  and disc magnet  219 ′ and positions disc magnet  219 ′ away from the proximal end of the proximal-most coil  217 . The polymer non-magnetic disc spacer  219 ″ is used so that the magnetic member  202  can be centered in a zero or start position slightly proximal of the proximal-most coil  217  of the driver coil pack  188 . This allows the magnetic member to be attracted by the proximal-most coil  217  at the initiation of the lancing cycle instead of being passive in the forward drive portion of the lancing cycle. 
     An inner lumen of the polymer non-magnetic disc  219 ″ can be configured to allow the magnetic member  202  to pass axially there through while an inner lumen of the disc magnet  219 ′ can be configured to allow the elongate coupler shaft  184  to pass through but not large enough for the magnetic member  202  to pass through. This results in the magnetic member  202  being attracted to the disc magnet  219 ′ and coming to rest with the proximal surface of the magnetic member  202  against a distal surface of the disc magnet  219 ′. This arrangement provides for a positive and repeatable stop for the magnetic member, and hence the lancet. A similar configuration could also be used for the bar magnet  219  discussed above. 
     Typically, when the electrical current in the coils  214 - 217  of the driver coil pack  188  is off, a magnetic member  202  made of soft iron is attracted to the bar magnet  219  or disc magnet  219 ′. The magnetic field of the driver coil pack  188  and the bar magnet  219  or disc magnet  219 ′, or any other suitable magnet, can be configured such that when the electrical current in the coils  214 - 217  is turned on, the leakage magnetic field from the coils  214 - 217  has the same polarity as the bar magnet  219  or disc magnet  219 ′. This results in a magnetic force that repels the magnetic member  202  from the bar magnet  219  or disc magnet  219 ′ and attracts the magnetic member  202  to the activated coils  214 - 217 . For this configuration, the bar magnet  219  or disc magnet thus act to facilitate acceleration of the magnetic member  202  as opposed to working against the acceleration. 
     Electrical conductors  222  couple the driver coil pack  188  with the processor  193  which can be configured or programmed to control the current flow in the coils  214 - 217  of the driver coil pack  188  based on position feedback from the position sensor  191 , which is coupled to the processor  193  by electrical conductors  194 . A power source  225  is electrically coupled to the processor  193  and provides electrical power to operate the processor  193  and power the coil driver pack  188 . The power source  225  may be one or more batteries that provide direct current power to the  193  processor. 
       FIG. 23  shows a transverse cross sectional view of drive coupler  185  in more detail. The drive head  198  of the lancet  183  is disposed within the drive coupler  185  with a first retaining rail  226  and second retaining rail  227  capturing the drive head  198  while allowing the drive head  198  to be inserted laterally into the drive coupler  185  and retracted laterally with minimal mechanical resistance. The drive coupler  185  may optionally be configured to include snap ridges  228  which allow the drive head  198  to be laterally inserted and retracted, but keep the drive head  198  from falling out of the drive coupler  185  unless a predetermined amount of externally applied lateral force is applied to the drive head  198  of the lancet  183  towards the lateral opening  231  of the drive coupler  185 .  FIG. 27  shows an enlarged side view into the coupler opening  231  of the drive coupler  185  showing the snap ridges  228  disposed in the lateral opening  231  and the retaining rails  226  and  227 .  FIG. 28  shows an enlarged front view of the drive coupler  185 . The drive coupler  185  can be made from an alloy such as stainless steel, titanium or aluminum, but may also be made from a suitable polymer such as ABS, PVC, polycarbonate plastic or the like. The drive coupler may be open on both sides allowing the drive head and lancet to pass through. 
     Referring to  FIG. 24 , the magnetic member  202  is disposed about and secured to the elongate coupler shaft  184 . The magnetic member  202  is disposed within the axial lumen  232  of the fourth coil  217 . The driver coil pack  188  is secured to the base  213 . In  FIG. 25  the position sensor  191  is secured to the base  213  with the first body portion  208  of the position sensor  191  disposed opposite the second body portion  209  of the position sensor  191  with the first and second body portions  208  and  209  of the position sensor  191  separated by the gap or slot  207 . The elongate coupler shaft  184  is slidably disposed within the gap  207  between the first and second body portions  208  and  209  of the position sensor  191 . The optical encoder flag  206  is secured to the elongate coupler shaft  184  and disposed between the first body portion  208  and second body portion  209  of the position sensor  191 . Referring to  FIG. 26 , the proximal portion  192  of the elongate coupler shaft  184  is disposed within the guide lumen  212  of the coupler shaft guide  211 . The guide lumen  212  of the coupler shaft guide  211  may be lined with a low friction material such as Teflon® or the like to reduce friction of the elongate coupler shaft  184  during the power stroke of the lancing device  180 . 
     Referring to  FIGS. 29A-29C , a flow diagram is shown that describes the operations performed by the processor  193  in controlling the lancet  183  of the lancing device  180  discussed above during an operating cycle.  FIGS. 30-36  illustrate the interaction of the lancet  183  and skin  233  of the patient&#39;s finger  234  during an operation cycle of the lancet device  183 . The processor  193  operates under control of programming steps that are stored in an associated memory. When the programming steps are executed, the processor  193  performs operations as described herein. Thus, the programming steps implement the functionality of the operations described with respect to the flow diagram of  FIG. 29 . The processor  193  can receive the programming steps from a program product stored in recordable media, including a direct access program product storage device such as a hard drive or flash ROM, a removable program product storage device such as a floppy disk, or in any other manner known to those of skill in the art. The processor  193  can also download the programming steps through a network connection or serial connection. 
     In the first operation, represented by the flow diagram box numbered  245  in  FIG. 29A , the processor  193  initializes values that it stores in memory relating to control of the lancet, such as variables that it uses to keep track of the controllable driver  179  during movement. For example, the processor may set a clock value to zero and a lancet position value to zero or to some other initial value. The processor  193  may also cause power to be removed from the coil pack  188  for a period of time, such as for about 10 ms, to allow any residual flux to dissipate from the coils. 
     In the initialization operation, the processor  193  also causes the lancet to assume an initial stationary position. When in the initial stationary position, the lancet  183  is typically fully retracted such that the magnetic member  202  is positioned substantially adjacent the fourth coil  217  of the driver coil pack  188 , shown in  FIG. 21  above. The processor  193  can move the lancet  183  to the initial stationary position by pulsing an electrical current to the fourth coil  217  to thereby attract the magnetic member  202  on the lancet  183  to the fourth coil  217 . Alternatively, the magnetic member can be positioned in the initial stationary position by virtue of a permanent magnet, such as bar magnet  219 , disc magnet  219 ′ or any other suitable magnet as discussed above with regard to the tissue penetration device illustrated in  FIGS. 20 and 21 . 
     In the next operation, represented by the flow diagram box numbered  247 , the processor  193  energizes one or more of the coils in the coil pack  188 . This should cause the lancet  183  to begin to move (i.e., achieve a non-zero speed) toward the skin target  233 . The processor  193  then determines whether or not the lancet is indeed moving, as represented by the decision box numbered  249 . The processor  193  can determine whether the lancet  183  is moving by monitoring the position of the lancet  183  to determine whether the position changes over time. The processor  193  can monitor the position of the lancet  183  by keeping track of the position of the optical encoder flag  206  secured to the elongate coupler shaft  184  wherein the encoder  191  produces a signal coupled to the processor  193  that indicates the spatial position of the lancet  183 . 
     If the processor  193  determines (via timeout without motion events) that the lancet  183  is not moving (a “No” result from the decision box  249 ), then the process proceeds to the operation represented by the flow diagram box numbered  253 , where the processor deems that an error condition is present. This means that some error in the system is causing the lancet  183  not to move. The error may be mechanical, electrical, or software related. For example, the lancet  183  may be stuck in the stationary position because something is impeding its movement. 
     If the processor  193  determines that the lancet  183  is indeed moving (a “Yes” result from the decision box numbered  249 ), then the process proceeds to the operation represented by the flow diagram box numbered  257 . In this operation, the processor  193  causes the lancet  183  to continue to accelerate and launch toward the skin target  233 , as indicated by the arrow  235  in  FIG. 30 . The processor  193  can achieve acceleration of the lancet  183  by sending an electrical current to an appropriate coil  214 - 217  such that the coil  214 - 217  exerts an attractive magnetic launching force on the magnetic member  202  and causes the magnetic member  202  and the lancet  183  coupled thereto to move in a desired direction. For example, the processor  193  can cause an electrical current to be sent to the third coil  216  so that the third coil  216  attracts the magnetic member  202  and causes the magnetic member  202  to move from a position adjacent the fourth coil  217  toward the third coil  216 . The processor preferably determines which coil  214 - 217  should be used to attract the magnetic member  202  based on the position of the magnetic member  202  relative to the coils  214 - 217 . In this manner, the processor  193  provides a controlled force to the lancet that controls the movement of the lancet. 
     During this operation, the processor  193  periodically or continually monitors the position and/or velocity of the lancet  183 . In keeping track of the velocity and position of the lancet  183  as the lancet  183  moves towards the patient&#39;s skin  233  or other tissue, the processor  193  also monitors and adjusts the electrical current to the coils  214 - 217 . In some embodiments, the processor  193  applies current to an appropriate coil  214 - 217  such that the lancet  183  continues to move according to a desired direction and acceleration. In the instant case, the processor  193  applies current to the appropriate coil  214 - 217  that will cause the lancet  183  to continue to move in the direction of the patient&#39;s skin  233  or other tissue to be penetrated. 
     The processor  193  may successively transition the current between coils  214 - 217  so that as the magnetic member  202  moves past a particular coil  214 - 217 , the processor  193  then shuts off current to that coil  214 - 217  and then applies current to another coil  214 - 217  that will attract the magnetic member  202  and cause the magnetic member  202  to continue to move in the desired direction. In transitioning current between the coils  214 - 217 , the processor  193  can take into account various factors, including the speed of the lancet  183 , the position of the lancet  183  relative to the coils  214 - 217 , the number of coils  214 - 217 , and the level of current to be applied to the coils  214 - 217  to achieve a desired speed or acceleration. 
     In the next operation, the processor  193  determines whether the cutting or distal end tip  196  of the lancet  183  has contacted the patient&#39;s skin  233 , as shown in  FIG. 31  and as represented by the decision box numbered  265  in  FIG. 29B . The processor  193  may determine whether the lancet  183  has made contact with the target tissue  233  by a variety of methods, including some that rely on parameters which are measured prior to initiation of a lancing cycle and other methods that are adaptable to use during a lancing cycle without any predetermined parameters. 
     In one embodiment, the processor  193  determines that the skin has been contacted when the end tip  196  of the lancet  183  has moved a predetermined distance with respect to its initial position. If the distance from the tip  961  of the lancet  183  to the target tissue  233  is known prior to initiation of lancet  183  movement, the initial position of the lancet  183  is fixed and known, and the movement and position of the lancet  183  can be accurately measured during a lancing cycle, then the position and time of lancet contact can be determined. 
     This method requires an accurate measurement of the distance between the lancet tip  196  and the patient&#39;s skin  233  when the lancet  183  is in the zero time or initial position. This can be accomplished in a number of ways. One way is to control all of the mechanical parameters that influence the distance from the lancet tip  196  to the patient&#39;s tissue or a surface of the lancing device  180  that will contact the patient&#39;s skin  233 . This could include the start position of the magnetic member  202 , magnetic path tolerance, magnetic member  202  dimensions, driver coil pack  188  location within the lancing device  180  as a whole, length of the elongate coupling shaft  184 , placement of the magnetic member  202  on the elongate coupling shaft  184 , length of the lancet  183  etc. 
     If all these parameters, as well as others can be suitably controlled in manufacturing with a tolerance stack-up that is acceptable, then the distance from the lancet tip  196  to the target tissue  233  can be determined at the time of manufacture of the lancing device  180 . The distance could then be programmed into the memory of the processor  193 . If an adjustable feature is added to the lancing device  180 , such as an adjustable length elongate coupling shaft  184 , this can accommodate variations in all of the parameters noted above, except length of the lancet  183 . An electronic alternative to this mechanical approach would be to calibrate a stored memory contact point into the memory of the processor  193  during manufacture based on the mechanical parameters described above. 
     In another embodiment, moving the lancet tip  196  to the target tissue  233  very slowly and gently touching the skin  233  prior to actuation can accomplish the distance from the lancet tip  196  to the tissue  233 . The position sensor can accurately measure the distance from the initialization point to the point of contact, where the resistance to advancement of the lancet  183  stops the lancet movement. The lancet  183  is then retracted to the initialization point having measured the distance to the target tissue  233  without creating any discomfort to the user. 
     In another embodiment, the processor  193  may use software to determine whether the lancet  183  has made contact with the patient&#39;s skin  233  by measuring for a sudden reduction in velocity of the lancet  183  due to friction or resistance imposed on the lancet  183  by the patient&#39;s skin  233 . The optical encoder  191  measures displacement of the lancet  183 . The position output data provides input to the interrupt input of the processor  193 . The processor  193  also has a timer capable of measuring the time between interrupts. The distance between interrupts is known for the optical encoder  191 , so the velocity of the lancet  183  can be calculated by dividing the distance between interrupts by the time between the interrupts. 
     This method requires that velocity losses to the lancet  183  and elongate coupler  184  assembly due to friction are known to an acceptable level so that these velocity losses and resulting deceleration can be accounted for when establishing a deceleration threshold above which contact between lancet tip  196  and target tissue  233  will be presumed. This same concept can be implemented in many ways. For example, rather than monitoring the velocity of the lancet  183 , if the processor  193  is controlling the lancet driver in order to maintain a fixed velocity, the power to the driver  188  could be monitored. If an amount of power above a predetermined threshold is required in order to maintain a constant velocity, then contact between the tip of the lancet  196  and the skin  233  could be presumed. 
     In yet another embodiment, the processor  193  determines skin  233  contact by the lancet  183  by detection of an acoustic signal produced by the tip  196  of the lancet  183  as it strikes the patient&#39;s skin  233 . Detection of the acoustic signal can be measured by an acoustic detector  236  placed in contact with the patient&#39;s skin  233  adjacent a lancet penetration site  237 , as shown in  FIG. 31 . Suitable acoustic detectors  236  include piezo electric transducers, microphones and the like. The acoustic detector  236  transmits an electrical signal generated by the acoustic signal to the processor  193  via electrical conductors  238 . In another embodiment, contact of the lancet  183  with the patient&#39;s skin  233  can be determined by measurement of electrical continuity in a circuit that includes the lancet  183 , the patient&#39;s finger  234  and an electrical contact pad  240  that is disposed on the patient&#39;s skin  233  adjacent the contact site  237  of the lancet  183 , as shown in  FIG. 31 . In this embodiment, as soon as the lancet  183  contacts the patient&#39;s skin  233 , the circuit  239  is completed and current flows through the circuit  239 . Completion of the circuit  239  can then be detected by the processor  193  to confirm skin  233  contact by the lancet  183 . 
     If the lancet  183  has not contacted the target skin  233 , then the process proceeds to a timeout operation, as represented by the decision box numbered  267  in  FIG. 29B . In the timeout operation, the processor  193  waits a predetermined time period. If the timeout period has not yet elapsed (a “No” outcome from the decision box  267 ), then the processor continues to monitor whether the lancet has contacted the target skin  233 . The processor  193  preferably continues to monitor the position and speed of the lancet  183 , as well as the electrical current to the appropriate coil  214 - 217  to maintain the desired lancet  183  movement. 
     If the timeout period elapses without the lancet  183  contacting the skin (a “Yes” output from the decision box  267 ), then it is deemed that the lancet  183  will not contact the skin and the process proceeds to a withdraw phase, where the lancet is withdrawn away from the skin  233 , as discussed more fully below. The lancet  183  may not have contacted the target skin  233  for a variety of reasons, such as if the patient removed the skin  233  from the lancing device or if something obstructed the lancet  183  prior to it contacting the skin. 
     The processor  193  may also proceed to the withdraw phase prior to skin contact for other reasons. For example, at some point after initiation of movement of the lancet  183 , the processor  193  may determine that the forward acceleration of the lancet  183  towards the patient&#39;s skin  233  should be stopped or that current to all coils  214 - 217  should be shut down. This can occur, for example, if it is determined that the lancet  183  has achieved sufficient forward velocity, but has not yet contacted the skin  233 . In one embodiment, the average penetration velocity of the lancet  183  from the point of contact with the skin to the point of maximum penetration may be about 2.0 to about 10.0 m/s, specifically, about 3.8 to about 4.2 m/s. In another embodiment, the average penetration velocity of the lancet may be from about 2 to about 8 meters per second, specifically, about 2 to about 4 m/s. 
     The processor  193  can also proceed to the withdraw phase if it is determined that the lancet  183  has fully extended to the end of the power stroke of the operation cycle of lancing procedure. In other words, the process may proceed to withdraw phase when an axial center  241  of the magnetic member  202  has moved distal of an axial center  242  of the first coil  214  as show in  FIG. 21 . In this situation, any continued power to any of the coils  214 - 217  of the driver coil pack  188  serves to decelerate the magnetic member  202  and thus the lancet  183 . In this regard, the processor  193  considers the length of the lancet  183  (which can be stored in memory) the position of the lancet  183  relative to the magnetic member  202 , as well as the distance that the lancet  183  has traveled. 
     With reference again to the decision box  265  in  FIG. 29B , if the processor  193  determines that the lancet  183  has contacted the skin  233  (a “Yes” outcome from the decision box  265 ), then the processor  193  can adjust the speed of the lancet  183  or the power delivered to the lancet  183  for skin penetration to overcome any frictional forces on the lancet  183  in order to maintain a desired penetration velocity of the lancet. The flow diagram box numbered  267  represents this. 
     As the velocity of the lancet  183  is maintained after contact with the skin  233 , the distal tip  196  of the lancet  183  will first begin to depress or tent the contacted skin  237  and the skin  233  adjacent the lancet  183  to form a tented portion  243  as shown in  FIG. 32  and further shown in  FIG. 33 . As the lancet  183  continues to move in a distal direction or be driven in a distal direction against the patient&#39;s skin  233 , the lancet  183  will eventually begin to penetrate the skin  233 , as shown in  FIG. 34 . Once penetration of the skin  233  begins, the static force at the distal tip  196  of the lancet  183  from the skin  233  will become a dynamic cutting force, which is generally less than the static tip force. As a result in the reduction of force on the distal tip  196  of the lancet  183  upon initiation of cutting, the tented portion  243  of the skin  233  adjacent the distal tip  196  of the lancet  183  which had been depressed as shown in  FIGS. 32 and 24  will spring back as shown in  FIG. 34 . 
     In the next operation, represented by the decision box numbered  271  in  FIG. 29B , the processor  193  determines whether the distal end  196  of the lancet  183  has reached a brake depth. The brake depth is the skin penetration depth for which the processor  193  determines that deceleration of the lancet  183  is to be initiated in order to achieve a desired final penetration depth  244  of the lancet  183  as show in  FIG. 35 . The brake depth may be pre-determined and programmed into the processor&#39;s memory, or the processor  193  may dynamically determine the brake depth during the actuation. The amount of penetration of the lancet  183  in the skin  233  of the patient may be measured during the operation cycle of the lancet device  180 . In addition, as discussed above, the penetration depth necessary for successfully obtaining a useable sample can depend on the amount of tenting of the skin  233  during the lancing cycle. The amount of tenting of the patient&#39;s skin  233  can in turn depend on the tissue characteristics of the patient such as elasticity, hydration etc. A method for determining these characteristics is discussed below with regard to skin  233  tenting measurements during the lancing cycle and illustrated in  FIGS. 37-41 . 
     Penetration measurement can be carried out by a variety of methods that are not dependent on measurement of tenting of the patient&#39;s skin. In one embodiment, the penetration depth of the lancet  183  in the patient&#39;s skin  233  is measured by monitoring the amount of capacitance between the lancet  183  and the patient&#39;s skin  233 . In this embodiment, a circuit includes the lancet  183 , the patient&#39;s finger  234 , the processor  193  and electrical conductors connecting these elements. As the lancet  183  penetrates the patient&#39;s skin  233 , the greater the amount of penetration, the greater the surface contact area between the lancet  183  and the patient&#39;s skin  233 . As the contact area increases, so does the capacitance between the skin  233  and the lancet  183 . The increased capacitance can be easily measured by the processor  193  using methods known in the art and penetration depth can then be correlated to the amount of capacitance. The same method can be used by measuring the electrical resistance between the lancet  183  and the patient&#39;s skin. 
     If the brake depth has not yet been reached, then a “No” results from the decision box  271  and the process proceeds to the timeout operation represented by the flow diagram box numbered  273 . In the timeout operation, the processor  193  waits a predetermined time period. If the timeout period has not yet elapsed (a “No” outcome from the decision box  273 ), then the processor continues to monitor whether the brake depth has been reached. If the timeout period elapses without the lancet  183  achieving the brake depth (a “Yes” output from the decision box  273 ), then the processor  193  deems that the lancet  183  will not reach the brake depth and the process proceeds to the withdraw phase, which is discussed more fully below. This may occur, for example, if the lancet  183  is stuck at a certain depth. 
     With reference again to the decision box numbered  271  in  FIG. 29B , if the lancet does reach the brake depth (a “Yes” result), then the process proceeds to the operation represented by the flow diagram box numbered  275 . In this operation, the processor  193  causes a braking force to be applied to the lancet to thereby reduce the speed of the lancet  183  to achieve a desired amount of final skin penetration depth  244 , as shown in  FIG. 26 . Note that  FIGS. 32 and 33  illustrate the lancet making contact with the patient&#39;s skin and deforming or depressing the skin prior to any substantial penetration of the skin. The speed of the lancet  183  is preferably reduced to a value below a desired threshold and is ultimately reduced to zero. The processor  193  can reduce the speed of the lancet  183  by causing a current to be sent to a  214 - 217  coil that will exert an attractive braking force on the magnetic member  202  in a proximal direction away from the patient&#39;s tissue or skin  233 , as indicated by the arrow  290  in  FIG. 36 . Such a negative force reduces the forward or distally oriented speed of the lancet  183 . The processor  193  can determine which coil  214 - 217  to energize based upon the position of the magnetic member  202  with respect to the coils  214 - 217  of the driver coil pack  188 , as indicated by the position sensor  191 . 
     In the next operation, the process proceeds to the withdraw phase, as represented by the flow diagram box numbered  277 . The withdraw phase begins with the operation represented by the flow diagram box numbered  279  in  FIG. 29C . Here, the processor  193  allows the lancet  183  to settle at a position of maximum skin penetration  244 , as shown in  FIG. 35 . In this regard, the processor  193  waits until any motion in the lancet  183  (due to vibration from impact and spring energy stored in the skin, etc.) has stopped by monitoring changes in position of the lancet  183 . The processor  193  preferably waits until several milliseconds (ms), such as on the order of about 8 ms, have passed with no changes in position of the lancet  183 . This is an indication that movement of the lancet  183  has ceased entirely. In some embodiments, the lancet may be allowed to settle for about 1 to about 2000 milliseconds, specifically, about 50 to about 200 milliseconds. For other embodiments, the settling time may be about 1 to about 200 milliseconds. 
     It is at this stage of the lancing cycle that a software method can be used to measure the amount of tenting of the patient&#39;s skin  233  and thus determine the skin  233  characteristics such as elasticity, hydration and others. Referring to  FIGS. 37-41 , a lancet  183  is illustrated in various phases of a lancing cycle with target tissue  233 .  FIG. 37  shows tip  196  of lancet  183  making initial contact with the skin  233  at the point of initial impact. 
       FIG. 38  illustrates an enlarged view of the lancet  183  making initial contact with the tissue  233  shown in  FIG. 37 . In  FIG. 39 , the lancet tip  196  has depressed or tented the skin  233  prior to penetration over a distance of X, as indicated by the arrow labeled X in  FIG. 39 . In  FIG. 40 , the lancet  183  has reached the full length of the cutting power stroke and is at maximum displacement. In this position, the lancet tip  196  has penetrated the tissue  233  a distance of Y, as indicated by the arrow labeled Y in  FIG. 39 . As can be seen from comparing  FIG. 38  with  FIG. 40 , the lancet tip  196  was displaced a total distance of X plus Y from the time initial contact with the skin  233  was made to the time the lancet tip  196  reached its maximum extension as shown in  FIG. 40 . However, the lancet tip  196  has only penetrated the skin  233  a distance Y because of the tenting phenomenon. 
     At the end of the power stroke of the lancet  183 , as discussed above with regard to  FIG. 26  and box  279  of  FIG. 29C , the processor  193  allows the lancet to settle for about 8 msec. It is during this settling time that the skin  233  rebounds or relaxes back to approximately its original configuration prior to contact by the lancet  183  as shown in  FIG. 41 . The lancet tip  196  is still buried in the skin to a depth of Y, as shown in  FIG. 41 , however the elastic recoil of the tissue has displaced the lancet rearward or retrograde to the point of inelastic tenting that is indicated by the arrows Z in  FIG. 41 . During the rearward displacement of the lancet  183  due to the elastic tenting of the tissue  233 , the processor reads and stores the position data generated by the position sensor  191  and thus measures the amount of elastic tenting, which is the difference between X and Z. 
     The tenting process and retrograde motion of the lancet  183  during the lancing cycle is illustrated graphically in  FIG. 42  which shows both a velocity versus time graph and a position versus time graph of a lancet tip  196  during a lancing cycle that includes elastic and inelastic tenting. In  FIG. 42 , from point 0 to point A, the lancet  183  is being accelerated from the initialization position or zero position. From point A to point B, the lancet is in ballistic or coasting mode, with no additional power being delivered. At point B, the lancet tip  196  contacts the tissue  233  and begins to tent the skin  233  until it reaches a displacement C. As the lancet tip  196  approaches maximum displacement, braking force is applied to the lancet  183  until the lancet comes to a stop at point D. The lancet  183  then recoils in a retrograde direction during the settling phase of the lancing cycle indicated between D and E. Note that the magnitude of inelastic tenting indicated in  FIG. 42  is exaggerated for purposes of illustration. 
     The amount of inelastic tenting indicated by Z tends to be fairly consistent and small compared to the magnitude of the elastic tenting. Generally, the amount of inelastic tenting Z can be about 120 to about 140 microns. As the magnitude of the inelastic tenting has a fairly constant value and is small compared to the magnitude of the elastic tenting for most patients and skin types, the value for the total amount of tenting for the penetration stroke of the lancet  183  is effectively equal to the rearward displacement of the lancet during the settling phase as measured by the processor  193  plus a predetermined value for the inelastic recoil, such as 130 microns. Inelastic recoil for some embodiments can be about 100 to about 200 microns. The ability to measure the magnitude of skin  233  tenting for a patient is important to controlling the depth of penetration of the lancet tip  196  as the skin is generally known to vary in elasticity and other parameters due to age, time of day, level of hydration, gender and pathological state. 
     This value for total tenting for the lancing cycle can then be used to determine the various characteristics of the patient&#39;s skin  233 . Once a body of tenting data is obtained for a given patient, this data can be analyzed in order to predict the total lancet displacement, from the point of skin contact, necessary for a successful lancing procedure. This enables the tissue penetration device to achieve a high success rate and minimize pain for the user. A rolling average table can be used to collect and store the tenting data for a patient with a pointer to the last entry in the table. When a new entry is input, it can replace the entry at the pointer and the pointer advances to the next value. When an average is desired, all the values are added and the sum divided by the total number of entries by the processor  193 . Similar techniques involving exponential decay (multiply by 0.95, add 0.05 times current value, etc.) are also possible. 
     With regard to tenting of skin  233  generally, some typical values relating to penetration depth are now discussed.  FIG. 43  shows a cross sectional view of the layers of the skin  233 . In order to reliably obtain a useable sample of blood from the skin  233 , it is desirable to have the lancet tip  196  reach the venuolar plexus of the skin. The stratum corneum is typically about 0.1 to about 0.6 mm thick and the distance from the top of the dermis to the venuole plexus can be from about 0.3 to about 1.4 mm. Elastic tenting can have a magnitude of up to about 2 mm or so, specifically, about 0.2 to about 2.0 mm, with an average magnitude of about 1 mm. This means that the amount of lancet displacement necessary to overcome the tenting can have a magnitude greater than the thickness of skin necessary to penetrate in order to reach the venuolar plexus. The total lancet displacement from point of initial skin contact may have an average value of about 1.7 to about 2.1 mm. In some embodiments, penetration depth and maximum penetration depth may be about 0.5 mm to about 5 mm, specifically, about 1 mm to about 3 mm. In some embodiments, a maximum penetration depth of about 0.5 to about 3 mm is useful. 
     Referring back to  FIG. 29C , in the next operation, represented by the flow diagram box numbered  280  in  FIG. 29C , the processor  193  causes a withdraw force to be exerted on the lancet  183  to retract the lancet  183  from the skin  233 , as shown by arrow  290  in  FIG. 36  The processor  193  sends a current to an appropriate coil  214 - 217  so that the coil  214 - 217  exerts an attractive distally oriented force on the magnetic member  202 , which should cause the lancet  183  to move backward in the desired direction. In some embodiments, the lancet  183  is withdrawn with less force and a lower speed than the force and speed during the penetration portion of the operation cycle. Withdrawal speed of the lancet in some embodiments can be about 0.004 to about 0.5 m/s, specifically, about 0.006 to about 0.01 m/s. In other embodiments, useful withdrawal velocities can be about 0.001 to about 0.02 meters per second, specifically, about 0.001 to about 0.01 meters per second. For embodiments that use a relatively slow withdrawal velocity compared to the penetration velocity, the withdrawal velocity may up to about 0.02 meters per second. For such embodiments, a ratio of the average penetration velocity relative to the average withdrawal velocity can be about 100 to about 1000. In embodiments where a relatively slow withdrawal velocity is not important, a withdrawal velocity of about 2 to about 10 meters per second may be used. 
     In the next operation, the processor  193  determines whether the lancet  183  is moving in the desired backward direction as a result of the force applied, as represented by the decision box numbered  281 . If the processor  193  determines that the lancet  183  is not moving (a “No” result from the decision box  281 ), then the processor  193  continues to cause a force to be exerted on the lancet  183 , as represented by the flow diagram box numbered  282 . The processor  193  may cause a stronger force to be exerted on the lancet  183  or may just continue to apply the same amount of force. The processor then again determines whether the lancet is moving, as represented by the decision box numbered  283 . If movement is still not detected (a “No” result from the decision box numbered  283 ), the processor  193  determines that an error condition is present, as represented by the flow diagram box numbered  284 . In such a situation, the processor preferably de-energizes the coils to remove force from the lancet, as the lack of movement may be an indication that the lancet is stuck in the skin of the patient and, therefore, that it may be undesirable to continue to attempt pull the lancet out of the skin. 
     With reference again to the decision boxes numbered  281  and  283  in  FIG. 29C , if the processor  193  determines that the lancet is indeed moving in the desired backward direction away from the skin  233 , then the process proceeds to the operation represented by the flow diagram box numbered  285 . In this operation, the backward movement of the lancet  183  continues until the lancet distal end has been completely withdrawn from the patient&#39;s skin  233 . As discussed above, in some embodiments the lancet  183  is withdrawn with less force and a lower speed than the force and speed during the penetration portion of the operation cycle. The relatively slow withdrawal of the lancet  183  may allow the blood from the capillaries of the patient accessed by the lancet  183  to follow the lancet  183  during withdrawal and reach the skin surface to reliably produce a usable blood sample. The process then ends. 
     Controlling the lancet motion over the operating cycle of the lancet  183  as discussed above allows a wide variety of lancet velocity profiles to be generated by the lancing device  180 . In particular, any of the lancet velocity profiles discussed above with regard to other embodiments can be achieved with the processor  193 , position sensor  191  and driver coil pack  188  of the lancing device  180 . 
     Another example of an embodiment of a velocity profile for a lancet can be seen in  FIGS. 44 and 45 , which illustrates a lancet profile with a fast entry velocity and a slow withdrawal velocity.  FIG. 44  illustrates an embodiment of a lancing profile showing velocity of the lancet versus position. The lancing profile starts at zero time and position and shows acceleration of the lancet towards the tissue from the electromagnetic force generated from the electromagnetic driver. At point A, the power is shut off and the lancet  183  begins to coast until it reaches the skin  233  indicated by B at which point, the velocity begins to decrease. At point C, the lancet  183  has reached maximum displacement and settles momentarily, typically for a time of about 8 milliseconds. 
     A retrograde withdrawal force is then imposed on the lancet by the controllable driver, which is controlled by the processor to maintain a withdrawal velocity of no more than about 0.006 to about 0.01 meters/second. The same cycle is illustrated in the velocity versus time plot of  FIG. 45  where the lancet is accelerated from the start point to point A. The lancet  183  coasts from A to B where the lancet tip  196  contacts tissue  233 . The lancet tip  196  then penetrates the tissue and slows with braking force eventually applied as the maximum penetration depth is approached. The lancet is stopped and settling between C and D. At D, the withdrawal phase begins and the lancet  183  is slowly withdrawn until it returns to the initialization point shown by E in  FIG. 45 . Note that retrograde recoil from elastic and inelastic tenting was not shown in the lancing profiles of  FIGS. 44 and 45  for purpose of illustration and clarity. 
     In another embodiment, the withdrawal phase may use a dual speed profile, with the slow 0.006 to 0.01 meter per second speed used until the lancet is withdrawn past the contact point with the tissue, then a faster speed of 0.01 to 1 meters per second may be used to shorten the complete cycle. 
     Referring to  FIG. 46 , another embodiment of a lancing device including a controllable driver  294  with a driver coil pack  295 , position sensor and lancet  183  are shown. The lancet  297  has a proximal end  298  and a distal end  299  with a sharpened point at the distal end  299  of the lancet  297 . A magnetic member  301  disposed about and secured to a proximal end portion  302  of the lancet  297  with a lancet shaft  303  being disposed between the magnetic member  301  and the sharpened point  299 . The lancet shaft  303  may be comprised of stainless steel, or any other suitable material or alloy. The lancet shaft  303  may have a length of about 3 mm to about 50 mm specifically, about 5 mm to about 15 mm. 
     The magnetic member  301  is configured to slide within an axial lumen  304  of the driver coil pack  295 . The driver coil pack  295  includes a most distal first coil  305 , a second coil  306 , which is axially disposed between the first coil  305  and a third coil  307 , and a proximal-most fourth coil  308 . Each of the first coil  305 , second coil  306 , third coil  307  and fourth coil  308  has an axial lumen. The axial lumens of the first through fourth coils  305 - 308  are configured to be coaxial with the axial lumens of the other coils and together form the axial lumen  309  of the driver coil pack  295  as a whole. Axially adjacent each of the coils  305 - 308  is a magnetic disk or washer  310  that augments completion of the magnetic circuit of the coils  305 - 308  during a lancing cycle of the driven coil pack  295 . The magnetic washers  310  of the embodiment of  FIG. 46  are made of ferrous steel but could be made of any other suitable magnetic material, such as iron or ferrite. The magnetic washers  310  have an outer diameter commensurate with an outer diameter of the driver coil pack  295  of about 4.0 to about 8.0 mm. The magnetic washers  310  have an axial thickness of about 0.05, to about 0.4 mm, specifically, about 0.15 to about 0.25 mm. The outer shell  294  of the coil pack is also made of iron or steel to complete the magnetic path around the coils and between the washers  310 . 
     Wrapping or winding an elongate electrical conductor  311  about the axial lumen  309  until a sufficient number of windings have been achieved forms the coils  305 - 308 . The elongate electrical conductor  311  is generally an insulated solid copper wire. The particular materials, dimensions number of coil windings etc. of the coils  305 - 308 , washers  310  and other components of the driver coil pack  295  can be the same or similar to the materials, dimensions number of coil windings etc. of the driver coil pack  188  discussed above. 
     Electrical conductors  312  couple the driver coil pack  295  with a processor  313  which can be configured or programmed to control the current flow in the coils  305 - 308  of the driver coil pack  295  based on position feedback from the position sensor  296 , which is coupled to the processor  313  by electrical conductors  315 . A power source  316  is electrically coupled to the processor  313  and provides electrical power to operate the processor  313  and power the driver coil pack  295 . The power source  316  may be one or more batteries (not shown) that provide direct current power to the processor  313  as discussed above. 
     The position sensor  296  is an analog reflecting light sensor that has a light source and light receiver in the form of a photo transducer  317  disposed within a housing  318  with the housing  318  secured in fixed spatial relation to the driver coil pack  295 . A reflective member  319  is disposed on or secured to a proximal end  320  of the magnetic member  301 . The processor  313  determines the position of the lancet  299  by first emitting light from the light source of the photo transducer  317  towards the reflective member  319  with a predetermined solid angle of emission. Then, the light receiver of the photo transducer  317  measures the intensity of light reflected from the reflective member  319  and electrical conductors  315  transmit the signal generated therefrom to the processor  313 . 
     By calibrating the intensity of reflected light from the reflective member  319  for various positions of the lancet  297  during the operating cycle of the driver coil pack  295 , the position of the lancet  297  can thereafter be determined by measuring the intensity of reflected light at any given moment. In one embodiment, the sensor  296  uses a commercially available LED/photo transducer module such as the OPB703 manufactured by Optek Technology, Inc., 1215 W. Crosby Road, Carrollton, Tex., 75006. This method of analog reflective measurement for position sensing can be used for any of the embodiments of lancet actuators discussed herein. In addition, any of the lancet actuators or drivers that include coils may use one or more of the coils to determine the position of the lancet  297  by using a magnetically permeable region on the lancet shaft  303  or magnetic member  301  itself as the core of a Linear Variable Differential Transformer (LVDT). 
     Referring to  FIGS. 47 and 48 , a flat coil lancet driver  325  is illustrated which has a main body housing  326  and a rotating frame  327 . The rotating frame  327  pivots about an axle  328  disposed between a base  329 , a top body portion  330  of the main body housing  326  and disposed in a pivot guide  331  of the rotating frame  327 . An actuator arm  332  of the rotating frame  327  extends radially from the pivot guide  331  and has a linkage receiving opening  333  disposed at an outward end  334  of the actuator arm  332 . A first end  335  of a coupler linkage  336  is coupled to the linkage receiving opening  333  of the actuator arm  332  and can rotate within the linkage receiving opening  333 . A second end  337  of the coupler linkage  336  is disposed within an opening at a proximal end  338  of a coupler translation member  341 . This configuration allows circumferential forces imposed upon the actuator arm  332  to be transferred into linear forces on a drive coupler  342  secured to a distal end  343  of the coupler translation member  341 . The materials and dimensions of the drive coupler  342  can be the same or similar to the materials and dimensions of the drive coupler  342  discussed above. 
     Opposite the actuator arm  332  of the rotating frame  327 , a translation substrate in the form of a coil arm  344  extends radially from the pivot guide  331  of the rotating frame  327 . The coil arm  344  is substantially triangular in shape. A flat coil  345  is disposed on and secured to the coil arm  344 . The flat coil  345  has leading segment  346  and a trailing segment  347 , both of which extend substantially orthogonal to the direction of motion of the segments  346  and  347  when the rotating frame  327  is rotating about the pivot guide  331 . The leading segment  346  is disposed within a first magnetically active region  348  generated by a first upper permanent magnet  349  secured to an upper magnet base  351  and a first lower permanent magnet  352  secured to a lower magnet base  353 . The trailing segment  347  is disposed within a second magnetically active region  354  generated by a second upper permanent magnet  355  secured to the upper magnet base  351  and a second lower permanent magnet secured to the lower magnet base  353 . 
     The magnetic field lines or circuit of the first upper and lower permanent magnets  349 ,  352 ,  355  and  356  can be directed upward from the first lower permanent magnet  352  to the first upper permanent magnet  349  or downward in an opposite direction. The magnetic field lines from the second permanent magnets  355  and  356  are also directed up or down, and will have a direction opposite to that of the first upper and lower permanent magnets  349  and  352 . This configuration produces rotational force on the coil arm  344  about the pivot guide  331  with the direction of the force determined by the direction of current flow in the flat coil  345 . 
     A position sensor  357  includes an optical encoder disk section  358  is secured to the rotating frame  327  which rotates with the rotating frame  327  and is read by an optical encoder  359  which is secured to the base  329 . The position sensor  357  determines the rotational position of the rotating frame  327  and sends the position information to a processor  360  which can have features which are the same or similar to the features of the processor  193  discussed above via electrical leads  361 . Electrical conductor leads  363  of the flat coil  345  are also electrically coupled to the processor  360 . 
     As electrical current is passed through the leading segment  346  and trailing segment  347  of the flat coil  345 , the rotational forces imposed on the segments  346  and  347  are transferred to the rotating frame  327  to the actuator arm  332 , through the coupler linkage  336  and coupler translation member  341  and eventually to the drive coupler  342 . In use, a lancet (not shown) is secured into the drive coupler  342 , and the flat coil lancet actuator  325  activated. The electrical current in the flat coil  345  determines the forces generated on the drive coupler  342 , and hence, a lancet secured to the coupler  342 . The processor  360  controls the electrical current in the flat coil  345  based on the position and velocity of the lancet as measured by the position sensor  357  information sent to the processor  360 . The processor  360  is able to control the velocity of a lancet in a manner similar to the processor  193  discussed above and can generate any of the desired lancet velocity profiles discussed above, in addition to others. 
       FIGS. 49 and 50  depict yet another embodiment of a controlled driver  369  having a driver coil pack  370  for a tissue penetration device. The driver coil pack  370  has a proximal end  371 , a distal end  372  and an axial lumen  373  extending from the proximal end  371  to the distal end  372 . An inner coil  374  is disposed about the axial lumen  373  and has a tapered configuration with increasing wraps per inch of an elongate conductor  375  in a distal direction. The inner coil  374  extends from the proximal end  371  of the coil driver pack  370  to the distal end  372  of the driver coil pack  370  with a major outer diameter or transverse dimension of about 1 to about 25 mm, specifically about 1 to about 12 mm. 
     The outer diameter or transverse dimension of the inner coil  374  at the proximal end  371  of the driver coil pack  370  is approximately equal to the diameter of the axial lumen  373  at the proximal end  371  of the coil pack  370 . That is, the inner coil  374  tapers to a reduce outer diameter proximally until there are few or no wraps of elongate electrical conductor  375  at the proximal end  371  of the driver coil pack  370 . The tapered configuration of the inner coil  374  produces an axial magnetic field gradient within the axial lumen  373  of the driver coil pack  370  when the inner coil  374  is activated with electrical current flowing through the elongate electrical conductor  375  of the inner coil  374 . 
     The axial magnetic field gradient produces a driving force for a magnetic member  376  disposed within the axial lumen  373  that drives the magnetic member  376  towards the distal end  372  of the driver coil pack  370  when the inner coil  374  is activated. The driving force on the magnetic member produced by the inner coil  374  is a smooth continuous force, which can produce a smooth and continuous acceleration of the magnetic member  376  and lancet  377  secured thereto. In some embodiments, the ratio of the increase in outer diameter versus axial displacement along the inner coil  374  in a distal direction can be from about 1 to about 0.08, specifically, about 1 to about 0.08. 
     An outer coil  378  is disposed on and longitudinally coextensive with the inner coil  374 . The outer coil  378  can have the same or similar dimensions and construction as the inner coil  374 , except that the outer coil  378  tapers proximally to an increased diameter or transverse dimension. The greater wraps per inch of elongate electrical conductor  379  in a proximal direction for the outer coil  378  produces a magnetic field gradient that drives the magnetic member  376  in a proximal direction when the outer coil  378  is activated with electrical current. This produces a braking or reversing effect on the magnetic member  376  during an operational cycle of the lancet  377  and driver coil pack  370 . The elongate electrical conductors  375  and  379  of the inner coil  374  and outer coil  378  are coupled to a processor  381 , which is coupled to an electrical power source  382 . The processor  381  can have properties similar to the other processors discussed above and can control the velocity profile of the magnetic member  376  and lancet  377  to produce any of the velocity profiles above as well as others. The driver coil pack  370  can be used as a substitute for the coil driver pack discussed above, with other components of the lancing device  180  being the same or similar. 
     Embodiments of driver or actuator mechanisms having been described, we now discuss embodiments of devices which can house lancets, collect samples of fluids, analyze the samples or any combination of these functions. These front-end devices may be integrated with actuators, such as those discussed above, or any other suitable driver or controllable driver. 
     Generally, most known methods of blood sampling require several steps. First, a measurement session is set up by gathering various articles such as lancets, lancet drivers, test strips, analyzing instrument, etc. Second, the patient must assemble the paraphernalia by loading a sterile lancet, loading a test strip, and arming the lancet driver. Third, the patient must place a finger against the lancet driver and using the other hand to activate the driver. Fourth, the patient must put down the lancet driver and place the bleeding finger against a test strip, (which may or may not have been loaded into an analyzing instrument). The patient must insure blood has been loaded onto the test strip and the analyzing instrument has been calibrated prior to such loading. Finally, the patient must dispose of all the blood-contaminated paraphernalia including the lancet. As such, integrating the lancing and sample collection features of a tissue penetration sampling device can achieve advantages with regard to patient convenience. 
       FIG. 51  shows a disposable sampling module  410 , which houses the lancet  412 . The lancet  412  has a head on a proximal end  416  which connects to the driver  438  and a distal end  414 , which lances the skin. The distal end  414  is disposed within the conduit  418 . The proximal end  416  extends into the cavity  420 . The sample reservoir  422  has a narrow input port  424  on the ergonomically contoured surface  426 , which is adjacent to the distal end  414  of the lancet  412 . The term ergonomically contoured, as used herein, generally means shaped to snugly fit a finger or other body portion to be lanced or otherwise tested placed on the surface. The sampling module  410  is capable of transporting the blood sample from the sample reservoir  422  through small passages (not shown), to an analytical region  428 . The analytical region  428  can include chemical, physical, optical, electrical or other means of analyzing the blood sample. The lancet, sample flow channel, sample reservoir and analytical region are integrated into the sampling module  410  in a single packaged unit. 
       FIG. 52  shows the chamber  430  in the housing  410 ′ where the sampling module  410  is loaded. The sampling module  410  is loaded on a socket  432  suspended with springs  434  and sits in slot  436 . A driver  438  is attached to the socket  432 . The driver  438  has a proximal end  440  and a distal end  442 . The driver  438  can be either a controllable driver or non-controllable driver any mechanical, such as spring or cam driven, or electrical, such as electromagnetically or electronically driven, means for advancing, stopping, and retracting the lancet. There is a clearance  444  between the distal end  442  of the driver  438  and the sensor  446 , which is attached to the chamber  430 . The socket  432  also contains an analyzer  448 , which is a system for analyzing blood. The analyzer  448  corresponds to the analytical region  428  on the module  410  when it is loaded into the socket  432 . 
       FIG. 53  shows a tissue penetration sampling device  411  with the sampling module  410  loaded into the socket  432  of housing  410 ′. The analytical region  428  and analyzer  448  overlap. The driver  438  fits into the cavity  420 . The proximal end  440  of the driver  438  abuts the distal end  416  of the lancet  412 . The patient&#39;s finger  450  sits on the ergonomically contoured surface  426 . 
       FIG. 54  shows a drawing of an alternate lancet configuration where the lancet  412  and driver  438  are oriented to lance the side of the finger  450  as it sits on the ergonomically contoured surface  426 . 
       FIG. 55  illustrates the orifice  452  and ergonomically contoured surface  426 . The conduit  418  has an orifice  452 , which opens on a blood well  454 . The sample input port  424  of the reservoir  422  also opens on the blood well  454 . The diameter of the sample input port  424  is significantly greater than the diameter of the orifice  452 , which is substantially the same diameter as the diameter of the lancet  412 . After the lancet is retracted, the blood flowing from the finger  450  will collect in the blood well  454 . The lancet  412  will have been retracted into the orifice  452  effectively blocking the passage of blood down the orifice  452 . The blood will flow from the blood well  454  through the sample input port  424  into the reservoir  422 . 
       FIG. 56  shows a drawing of the lancing event. The patient applies pressure by pushing down with the finger  450  on the ergonomically contoured surface  426 . This applies downward pressure on the sampling module  410 , which is loaded into the socket  432 . As the socket  432  is pushed downward it compresses the springs  434 . The sensor  446  makes contact with the distal end  442  of the driver  438  and thereby electrically detects the presence of the finger on the ergonomically contoured surface. The sensor can be a piezoelectric device, which detects this pressure and sends a signal to circuit  456 , which actuates the driver  438  and advances and then retracts the lancet  412  lancing the finger  450 . In another embodiment, the sensor  446  is an electric contact, which closes a circuit when it contacts the driver  438  activating the driver  438  to advance and retract the lancet  412  lancing the finger  450 . 
     An embodiment of a method of sampling includes a reduced number of steps that must be taken by a patient to obtain a sample and analysis of the sample. First, the patient loads a sampling module  410  with an embedded sterile lancet into the housing device  410 ′. Second, the patient initiates a lancing cycle by turning on the power to the device or by placing the finger to be lanced on the ergonomically contoured surface  426  and pressing down. Initiation of the sensor makes the sensor operational and gives control to activate the launcher. 
     The sensor is unprompted when the lancet is retracted after its lancing cycle to avoid unintended multiple lancing events. The lancing cycle consists of arming, advancing, stopping and retracting the lancet, and collecting the blood sample in the reservoir. The cycle is complete once the blood sample has been collected in the reservoir. Third, the patient presses down on the sampling module, which forces the driver  38  to make contact with the sensor, and activates the driver  438 . The lancet then pierces the skin and the reservoir collects the blood sample. 
     The patient is then optionally informed to remove the finger by an audible signal such as a buzzer or a beeper, and/or a visual signal such as an LED or a display screen. The patient can then dispose of all the contaminated parts by removing the sampling module  410  and disposing of it. In another embodiment, multiple sampling modules  410  may be loaded into the housing  410 ′ in the form of a cartridge (not shown). The patient can be informed by the tissue penetration sampling device  411  as to when to dispose of the entire cartridge after the analysis is complete. 
     In order to properly analyze a sample in the analytical region  428  of the sampling module  410 , it may be desirable or necessary to determine whether a fluid sample is present in a given portion of the sample flow channel, sample reservoir or analytical area. A variety of devices and methods for determining the presence of a fluid in a region are discussed below. 
     In  FIG. 57 , a thermal sensor  500  embedded in a substrate  502  adjacent to a surface  504  over which a fluid may flow. The surface may be, for example, a wall of a channel through which fluid may flow or a surface of a planar device over which fluid may flow. The thermal sensor  500  is in electrical communication with a signal-conditioning element  506 , which may be embedded in the substrate  502  or may be remotely located. The signal-conditioning element  506  receives the signal from the thermal sensor  500  and modifies it by means such as amplifying it and filtering it to reduce noise.  FIG. 57  also depicts a thermal sensor  508  located at an alternate location on the surface where it is directly exposed to the fluid flow. 
       FIG. 58  shows a configuration of a thermal sensor  500  adjacent to a separate heating element  510 . The thermal sensor  500  and the heating element  510  are embedded in a substrate  502  adjacent to a surface  504  over which a fluid may flow. In an alternate embodiment, one or more additional thermal sensors may be adjacent the heating element and may provide for increased signal sensitivity. The thermal sensor  500  is in electrical communication with a signal-conditioning element  506 , which may be embedded in the substrate  502  or may be remotely located. 
     The signal-conditioning element  506  receives the signal from the thermal sensor  500  and modifies it by means such as amplifying it and filtering it to reduce noise. The heating element  510  is in electrical communication with a power supply and control element  512 , which may be embedded in the substrate  502  or may be remotely located. The power supply and control element  512  provides a controlled source of voltage and current to the heating element  510 . 
       FIG. 59  depicts a configuration of thermal sensors  500  having three thermal sensor/heating element pairs ( 500 / 510 ), or detector elements, (with associated signal conditioning elements  506  and power supply and control elements  512  as described in  FIG. 58 ) embedded in a substrate  502  near each other alongside a surface  504 . The figure depicts the thermal sensors  500  arranged in a linear fashion parallel to the surface  504 , but any operable configuration may be used. In alternate embodiments, fewer than three or more than three thermal sensor/heating element pairs ( 500 / 510 ) may be used to indicate the arrival of fluid flowing across a surface  504 . In other embodiments, self-heating thermal sensors are used, eliminating the separate heating elements. 
     Embodiments of the present invention provide a simple and accurate methodology for detecting the arrival of a fluid at a defined location. Such detection can be particularly useful to define the zero- or start-time of a timing cycle for measuring rate-based reactions. This can be used in biochemical assays to detect a variety of analytes present in a variety of types of biological specimens or fluids and for rate-based reactions such as enzymatic reactions. Examples of relevant fluids include, blood, serum, plasma, urine, cerebral spinal fluid, saliva, enzymatic substances and other related substances and fluids that are well known in the analytical and biomedical art. The reaction chemistry for particular assays to analyze biomolecular fluids is generally well known, and selection of the particular assay used will depend on the biological fluid of interest. 
     Assays that are relevant to embodiments of the present invention include those that result in the measurement of individual analytes or enzymes, e.g., glucose, lactate, creatinine kinase, etc, as well as those that measure a characteristic of the total sample, for example, clotting time (coagulation) or complement-dependent lysis. Other embodiments for this invention provide for sensing of sample addition to a test article or arrival of the sample at a particular location within that article. 
     Referring now to  FIG. 60 , a substrate  502  defines a channel  520  having an interior surface  522  over which fluid may flow. An analysis site  524  is located within the channel  520  where fluid flowing in the channel  520  may contact the analysis site  524 . In various embodiments, the analysis site  524  may alternatively be upon the interior surface  522 , recessed into the substrate  502 , or essentially flush with the interior surface  522 .  FIG. 60 , depicts several possible locations for thermal sensors relative the substrate, the channel, and the analysis site; also, other locations may be useful and will depend upon the design of the device, as will be apparent to those of skill in art. 
     In use, thermal sensors may be omitted from one or more of the locations depicted in  FIG. 60 , depending on the intended design. A recess in the analysis site  524  may provide the location for a thermal sensor  526 , as may the perimeter of the analysis site provide the location for a thermal sensor  528 . One or more thermal sensors  530 ,  532 ,  534  may be located on the upstream side of the analysis site  524  (as fluid flows from right to left in  FIG. 60 ), or one or more thermal sensors  536 ,  538 ,  540  may be located on the downstream side of the analysis site  524 . 
     The thermal sensor may be embedded in the substrate near the surface, as thermal sensor  542  is depicted. In various other embodiments, the thermal sensor(s) may be located upon the interior surface, recessed into the interior surface, or essentially flush with the interior surface. Each thermal sensor may also be associated with a signal conditioning element, heating element, and power supply and control elements, as described above, and a single signal conditioning element, heating element, or power supply and control element may be associated with more than one thermal sensor. 
       FIG. 61  shows possible positions for thermal sensors relative to analysis sites  524  arranged in an array on a surface  556 . A recess in the analysis site  524  may provide the location for a thermal sensor  544 , as may the perimeter of the analysis site provide the location for a thermal sensor  546 . The edge of the surface surrounding the array of analysis sites may provide the position for one or more thermal sensors  548 . Thermal sensors may be positioned between analysis sites in a particular row  550  or column  552  of the array, or may be arranged on the diagonal  554 . 
     In various embodiments, the thermal sensor(s) may be may be embedded in the substrate near the surface or may be located upon the surface, recessed into the surface, or essentially flush with the surface. Each thermal sensor may also be associated with a signal conditioning elements, heating elements, and power supply and control elements, as described above, and a single signal conditioning element, heating element, or power supply and control element may be associated with more than one thermal sensor. 
     The use of small thermal sensors can be useful in miniaturized systems, such as microfluidic devices, which perform biomolecular analyses on very small fluid samples. Such analyses generally include passing a biomolecular fluid through, over, or adjacent to an analysis site and result in information about the biomolecular fluid being obtained through the use of reagents and/or test circuits and/or components associated with the analysis site. 
       FIG. 62  depicts several possible configurations of thermal sensors relative to channels and analysis sites. The device schematically depicted in  FIG. 62  may be, e.g., a microfluidic device for analyzing a small volume of a sample fluid, e.g. a biomolecular fluid. The device has a sample reservoir  560  for holding a quantity of a sample fluid. The sample fluid is introduced to the sample reservoir  560  via a sample inlet port  562  in fluid communication with the sample reservoir  560 . A thermal sensor  564  is located in or near the sample inlet port  562 . A primary channel  566  originates at the sample reservoir  560  and terminates at an outflow reservoir  568 . 
     One or more supplemental reservoirs  570  are optionally present and are in fluid communication with the primary channel  566  via one or more supplemental channels  572 , which lead from the supplemental reservoir  570  to the primary channel  566 . The supplemental reservoir  570  functions to hold fluids necessary for the operation of the assay, such as reagent solutions, wash solutions, developer solutions, fixative solutions, et cetera. In the primary channel  566  at a predetermined distance from the sample reservoir  560 , an array of analysis sites  574  is present. 
     Thermal sensors are located directly upstream (as fluid flows from right to left in the figure) from the array  576  and directly downstream from the array  578 . Thermal sensors are also located in the primary channel adjacent to where the primary channel originates at the sample reservoir  580  and adjacent to where the primary channel terminates at the outflow reservoir  582 . The supplemental channel provides the location for another thermal sensor  584 . 
     When the device is in operation, the thermal sensor  564  located in or near the sample inlet port  562  is used to indicate the arrival of the sample fluid, e.g. the biomolecular fluid, in the local environment of the thermal sensor, as described herein, and thus provides confirmation that the sample fluid has successfully been introduced into the device. The thermal sensor  580  located in the primary channel  566  adjacent to where the primary channel  566  originates at the sample reservoir  560  produces a signal indicating that sample fluid has started to flow from the sample reservoir  560  into the primary channel  566 . The thermal sensors  576  in the primary channel  566  just upstream from the array of analysis sites  574  may be used to indicate that the fluid sample is approaching the array  574 . Similarly, the thermal sensors  578  in the primary channel  566  just downstream from the array of analysis sites  574  may be used to indicate that the fluid sample has advanced beyond the array  574  and has thus contacted each analysis site. 
     The thermal sensor  584  in the supplemental channel  572  provides confirmation that the fluid contained within the supplemental reservoir  570  has commenced to flow therefrom. The thermal sensor  582  in the primary channel  566  adjacent to where the primary channel  566  terminates at the outflow reservoir  568  indicates when sample fluid arrives near the outflow reservoir  568 , which may then indicate that sufficient sample fluid has passed over the array of analysis sites  574  and that the analysis at the analysis sites is completed. 
     Embodiments of the invention provide for the use of a thermal sensor to detect the arrival of the fluid sample at a determined region, such as an analysis site, in the local environment of the thermal sensor near the thermal sensor. A variety of thermal sensors may be used. Thermistors are thermally-sensitive resistors whose prime function is to detect a predictable and precise change in electrical resistance when subjected to a corresponding change in temperature Negative Temperature Coefficient (NTC) thermistors exhibit a decrease in electrical resistance when subjected to an increase in temperature and Positive Temperature Coefficient (PTC) thermistors exhibit an increase in electrical resistance when subjected to an increase in temperature. 
     A variety of thermistors have been manufactured for over the counter use and application. Thermistors are capable of operating over the temperature range of −100 degrees to over 600 degrees Fahrenheit. Because of their flexibility, thermistors are useful for application to micro-fluidics and temperature measurement and control. 
     A change in temperature results in a corresponding change in the electrical resistance of the thermistor. This temperature change results from either an external transfer of heat via conduction or radiation from the sample or surrounding environment to the thermistor, or as an internal application of heat due to electrical power dissipation within the device. When a thermistor is operated in “self-heating” mode, the power dissipated in the device is sufficient to raise its temperature above the temperature of the local environment, which in turn more easily detects thermal changes in the conductivity of the local environment. 
     Thermistors are frequently used in “self heating” mode in applications such as fluid level detection, airflow detection and thermal conductivity materials characterization. This mode is particularly useful in fluid sensing, since a self-heating conductivity sensor dissipates significantly more heat in a fluid or in a moving air stream than it does in still air. 
     Embodiments of the invention may be designed such that the thermal sensor is exposed directly to the sample. However, it may also be embedded in the material of the device, e.g., in the wall of a channel meant to transport the sample. The thermal sensor may be covered with a thin coating of polymer or other protective material. 
     Embodiments of the device need to establish a baseline or threshold value of a monitored parameter such as temperature. Ideally this is established during the setup process. Once fluid movement has been initiated, the device continuously monitors for a significant change thereafter. The change level designated as “significant” is designed as a compromise between noise rejection and adequate sensitivity. The actual definition of the “zero- or start-time” may also include an algorithm determined from the time history of the data, i.e., it can be defined ranging from the exact instant that a simple threshold is crossed, to a complex mathematical function based upon a time sequence of data. 
     In use, a signal is read from a thermal sensor in the absence of the sample or fluid. The fluid sample is then introduced. The sample flows to or past the site of interest in the local environment of the thermal sensor, and the thermal sensor registers the arrival of the sample. The site of interest may include an analysis site for conducting, e.g., an enzymatic assay. Measuring the arrival of fluid at the site of interest thus indicates the zero- or start-time of the reaction to be performed. For detection of fluid presence, these sites may be any of a variety of desired locations along the fluidic pathway. Embodiments of the invention are particularly well suited to a microfluidic cartridge or platform, which provide the user with an assurance that a fluid sample has been introduced and has flowed to the appropriate locations in the platform. 
     A rate-based assay must measure both an initiation time, and some number of later time points, one of which is the end-point of the assay. Therefore, baseline or threshold value can be established, and then continuously monitored for a significant change thereafter; one such change is the arrival of the fluid sample that initiates the enzyme reaction. Baseline values are frequently established during the device setup process. The threshold is designed as a compromise between noise rejection and adequate sensitivity. The defined zero- or “start-time” can be defined ranging from the exact instant that a simple threshold is crossed, to the value algorithmically determined using a filter based on a time sequence of data. 
     Embodiments of the invention accomplish this in a variety of ways. In one embodiment, an initial temperature measurement is made at a thermal sensor without the sample present. The arrival of a sample changes causes the thermal sensor to register a new value. These values are then compared. 
     Another embodiment measures the change in thermal properties (such as thermal conductivity or thermal capacity) in the local environment of a thermal sensor caused by the arrival of a fluid sample. In general this is the operating principle of a class of devices known as “thermal conductivity sensors” or “heat flux sensors”. At least two hardware implementations have been used and are described above. One implementation utilizes a thermal sensor in a “self-heating mode.” In “self-heating mode,” a self-heating thermal sensor may utilize a positive temperature coefficient thermistor placed in or near the flow channel, e.g. located in the wall of the flow channel. 
     An electrical current is run through the thermistor, causing the average temperature of the thermistor to rise above that of the surrounding environment. The temperature can be determined from the electrical resistance, since it is temperature dependent. When fluid flows through the channel, it changes the local thermal conductivity near the thermistor (usually to become higher) and this causes a change in the average temperature of the thermistor. It also changes the thermal capacity, which modifies the thermal dynamic response. These changes give rise to a signal, which can be detected electronically by well-known means, and the arrival of the fluid can thereby be inferred. 
     A second hardware implementation requires a separate heating element in or near the flow channel, plus a thermal sensor arrangement in close proximity. Passing a current through the element provides heat to the local environment and establishes a local temperature detected by the thermocouple device. This temperature or its dynamic response is altered by the arrival of the fluid or blood in or near the local environment, similar to the previously described implementation, and the event is detected electronically. 
     The heating element can be operated in a controlled input mode, which may include controlling one or more of the following parameters—applied current, voltage or power—in a prescribed manner. When operating in controlled input mode, fluctuations of the temperature of the thermal sensor are monitored in order to detect the arrival of the fluid. 
     Alternatively, the heating element can be operated in such a fashion as to control the temperature of the thermal sensor in a prescribed manner. In this mode of operation, the resulting fluctuations in one or more of the input parameters to the heating element (applied current, voltage, and power) can be monitored in order to detect the arrival of the fluid. 
     In either of the above-described operating modes, the prescribed parameter can be held to a constant value or sequence of values that are held constant during specific phases of operation of the device. The prescribed parameter can also varied as a known function or waveform in time. 
     The change in the monitored parameters caused by the arrival of the fluid can be calculated in any of a number of ways, using methods well known in the art of signal processing. The signal processing methods allow the relation of the signal received prior to arrival of the fluid with the signal received upon arrival of the fluid to indicate that the fluid has arrived. For example, and after suitable signal filtering is applied, changes in the monitored value or the rate of change of the value of the signal can be monitored to detect the arrival of the fluid. Additionally, the arrival of fluid will cause a dynamic change in the thermodynamic properties of the local environment, such as thermal conductivity or thermal capacity. When the input parameter is a time varying function this change of thermodynamic properties will cause a phase shift of the measured parameter relative to the controlled parameter. This phase shift can be monitored to detect the arrival of the fluid. 
     It should also be noted that sensitivity to thermal noise and operating power levels could be reduced in these either of these modes of operation by a suitable choice of time-varying waveforms for the prescribed parameter, together with appropriate and well-known signal processing methods applied to the monitored parameters. However, these potential benefits may come at the cost of slower response time. 
     Referring to  FIG. 63 , an alternative embodiment of a tissue penetration sampling device is shown which incorporates disposable sampling module  590 , a lancet driver  591 , and an optional module cartridge  592  are shown. The optional module cartridge comprises a case body  593  having a storage cavity  594  for storing sampling modules  590 . A cover to this cavity has been left out for clarity. The cartridge further comprises a chamber  595  for holding the lancet driver  591 . The lancet driver has a preload adjustment knob  596 , by which the trigger point of the lancet driver may be adjusted. This insures a reproducible tension on the surface of the skin for better control of the depth of penetration and blood yield. In one embodiment, the sampling module  590  is removably attached to the lancet driver  591 , as shown, so that the sampling module  590  is disposable and the lancet driver  591  is reusable. In an alternative embodiment, the sampling module and lancet driver are contained within a single combined housing, and the combination sample acquisition module/lancet driver is disposable. The sampling module  590  includes a sampling site  597 , preferably having a concave depression  598 , or cradle, that can be ergonomically designed to conform to the shape of a user&#39;s finger or other anatomical feature (not shown). 
     The sampling site further includes an opening  599  located in the concave depression. The lancet driver  591  is used to fire a lancet contained within and guided by the sampling module  590  to create an incision on the user&#39;s finger when the finger is placed on the sampling site  597 . In one embodiment, the sampling site forms a substantially airtight seal at the opening when the skin is firmly pressed against the sampling site; the sampling site may additionally have a soft, compressible material surrounding the opening to further limit contamination of the blood sample by ambient air. “Substantially airtight” in this context means that only a negligible amount of ambient air may leak past the seal under ordinary operating conditions, the substantially airtight seal allowing the blood to be collected seamlessly. 
     Referring to  FIGS. 64 and 65 , the lancet  600  is protected in the integrated housing  601  that provides a cradle  602  for positioning the user&#39;s finger or other body part, a sampling port  603  within the cradle  602 , and a sample reservoir  603 ′ for collecting the resulting blood sample. The lancet  600  is a shaft with a distal end  604  sharpened to produce the incision with minimal pain. The lancet  600  further has an enlarged proximal end  605  opposite the distal end. Similar lancets are commonly known in the art. 
     Rather than being limited to a shaft having a sharp end, the lancet may have a variety of configurations known in the art, with suitable modifications being made to the system to accommodate such other lancet configurations, such configurations having a sharp instrument that exits the sampling port to create a wound from which a blood sample may be obtained. 
     In the figures, the lancet  600  is slidably disposed within a lancet guide  606  in the housing  601 , and movement of the lancet  600  within the lancet guide  606  is closely controlled to reduce lateral motion of the lancet, thereby reducing the pain of the lance stick. The sample acquisition module also includes a return stop  613 , which retains the lancet within the sample acquisition module. The sampling module has an attachment site  615  for attachment to the lancet driver. 
     The sampling module further includes a depth selector allowing the user to select one of several penetration depth settings. The depth selector is shown as a multi-position thumbwheel  607  having a graduated surface. By rotating the thumbwheel  607 , the user selects which part of the graduated surface contacts the enlarged proximal end  605  of the lancet to limit the movement of the lancet  600  within the lancet guide  606 . 
     The thumbwheel is maintained in the selected position by a retainer  608  having a protruding, rounded surface which engages at least one of several depressions  609  (e.g.dimples, grooves, or slots) in the thumbwheel  607 . The depressions  609  are spatially aligned to correspond with the graduated slope of the thumbwheel  607 , so that, when the thumbwheel  607  is turned, the depth setting is selected and maintained by the retainer  608  engaging the depression  609  corresponding to the particular depth setting selected. 
     In alternate embodiments, the retainer may be located on the depth selector and the depressions corresponding to the depth setting located on the housing such that retainer may functionally engage the depressions. Other similar arrangements for maintaining components in alignment are known in the art and may be used. In further alternate embodiments, the depth selector may take the form of a wedge having a graduated slope, which contacts the enlarged proximal end of the lancet, with the wedge being retained by a groove in the housing. 
     The sample reservoir  603 ′ includes an elongate, rounded chamber  610  within the housing  601  of the sample acquisition module. The chamber  610  has a flat or slightly spherical shape, with at least one side of the chamber  610  being formed by a smooth polymer, preferably absent of sharp corners. The sample reservoir  603 ′ also includes a sample input port  611  to the chamber  610 , which is in fluid communication with the sampling port  603 , and a vent  612  exiting the chamber. 
     A cover (not shown), preferably of clear material such as plastic, positions the lancet  600  and closes the chamber  603 ′, forming an opposing side of the chamber  603 ′. In embodiments where the cover is clear, the cover may serve as a testing means whereby the sample may be analyzed in the reservoir via optical sensing techniques operating through the cover. A clear cover will also aid in determining by inspection when the sample reservoir is full of the blood sample. 
       FIG. 66  shows a portion of the sampling module illustrating an alternate embodiment of the sample reservoir. The sample reservoir has a chamber  616  having a sample input port  617  joining the chamber  616  to a blood transport capillary channel  618 ; the chamber  616  also has a vent  619 . The chamber has a first side  620  that has a flat or slightly spherical shape absent of sharp corners and is formed by a smooth polymer. An elastomeric diaphragm  621  is attached to the perimeter of the chamber  616  and preferably is capable of closely fitting to the first side of the chamber  620 . 
     To control direction of blood flow, the sample reservoir is provided with a first check valve  622  located at the entrance  617  of the sample reservoir and a second check valve  623  leading to an exit channel  624  located at the vent  619 . Alternately, a single check valve (at the location  622 ) may be present controlling both flow into the chamber  616  via the blood transport capillary channel  618  and flow out of the chamber  616  into an optional alternate exit channel  625 . The sample reservoir has a duct  626  connecting to a source of variable pressure facilitating movement of the diaphragm  621 . 
     When the diaphragm  621  is flexed away from the first side of the chamber  620  (low pressure supplied from the source via duct  626 ), the first check valve  622  is open and the second check valve  623  is closed, aspiration of the blood sample into the sample reservoir follows. When the diaphragm  621  is flexed in the direction of the first side of the chamber  620  (high pressure supplied from the source via duct  626 ) with the first check valve  622  closed and the second check valve  623  open, the blood is forced out of the chamber  616 . The direction of movement and actuation speed of the diaphragm  621  can be controlled by the pressure source, and therefore the flow of the sample can be accelerated or decelerated. This feature allows not only reduced damage to the blood cells but also for the control of the speed by which the chamber  616  is filled. 
     While control of the diaphragm  621  via pneumatic means is described in this embodiment, mechanical means may alternately be used. Essentially, this micro diaphragm pump fulfills the aspiration, storage, and delivery functions. The diaphragm  621  may be used essentially as a pump to facilitate transfer of the blood to reach all areas required. Such required areas might be simple sample storage areas further downstream for assaying or for exposing the blood to a chemical sensor or other testing means. Delivery of the blood may be to sites within the sampling module or to sites outside the sampling module, i.e. a separate analysis device. 
     In an alternate embodiment, a chemical sensor or other testing means is located within the sampling module, and the blood is delivered to the chemical sensor or other testing means via a blood transfer channel in fluid communication with the sample reservoir. The components of the sampling module may be injection molded and the diaphragm may be fused or insertion molded as an integral component. 
       FIG. 67  depicts a portion of the disposable sampling module surrounding the sampling port  627 , including a portion of the sampling site cradle surface  628 . The housing of the sampling module includes a primary sample flow channel  629  that is a capillary channel connecting the sample input port to the sample reservoir. The primary sample flow channel  629  includes a primary channel lumenal surface  630  and a primary channel entrance  631 , the primary channel entrance  631  opening into the sample input port  627 . The sampling module may optionally include a supplemental sample flow channel  632  that is also a capillary channel having a supplemental channel lumenal surface  633  and a supplemental channel entrance  634 , the supplemental channel entrance  634  opening into the sample input port  627 . 
     The primary sample flow channel  629  has a greater cross-sectional area than the supplemental sample flow channel  632 , preferably by at least a factor of two. Thus, the supplemental sample flow channel  632  draws fluid faster than the primary sample flow channel  629 . When the first droplet of blood is received into the sample input port  627 , the majority of this droplet is drawn through the supplemental sample flow channel  632 . However, as the blood continues to flow from the incision into the sample input port  627 , most of this blood is drawn through the primary sample flow channel  629 , since the supplemental sample flow channel  632  is of limited capacity and is filled or mostly filled with the first blood droplet. This dual capillary channel configuration is particularly useful in testing where there is a concern with contamination of the sample, e.g. with debris from the lancet strike or (particularly in the case of blood gas testing) with air. 
     In order to improve blood droplet flow, some priming or wicking of the surface with blood is at times necessary to begin the capillary flow process. Portions of the surfaces of the sample input port  627  and the primary and supplemental (if present) sample flow channels  629 ,  632  are treated to render those surfaces hydrophilic. The surface modification may be achieved using mechanical, chemical, corona, or plasma treatment. Examples of such coatings and methods are marketed by AST Products (Billerica, Mass.) and Spire Corporation (Bedford, Mass.). 
     However, a complete blanket treatment of the surface could prove detrimental by causing blood to indiscriminately flow all over the surface and not preferentially through the capillary channel(s). This ultimately will result in losses of blood fluid. The particular surfaces which receive the treatment are selected to improve flow of blood from an incised finger on the sampling site cradle surface  628  through the sample input port  627  and at least one of the sample flow channels  629 ,  632  to the sample reservoir. Thus, the treatment process should be masked off and limited only to the selected surfaces. The masking process of selectively modifying the sampling surface from hydrophobic to hydrophilic may be done with mechanical masking techniques such as with metal shielding, deposited dielectric or conductive films, or electrical shielding means. 
     In some embodiments, the treated surfaces are limited to one or more of the following: the surface of the sampling port which lies between the sampling site cradle surface and the primary and supplemental sample flow channel, the surface immediately adjacent to the entrances to the primary and/or supplemental sample flow channels  631 ,  634  (both within the sample input port and within the sample flow channel), and the lumenal surface of the primary and/or supplemental sample flow channels  630 ,  633 . 
     Upon exiting the incision blood preferentially moves through the sample input port  627  into the supplementary sample flow channel  632  (if present) and into the primary sample flow channel  629  to the sample reservoir, resulting in efficient capture of the blood. Alternatively, the substrate material may be selected to be hydrophilic or hydrophobic, and a portion of the surface of the substrate material may be treated for the opposite characteristic. 
     In an embodiment,  FIG. 67  a membrane  635  at the base of the sample input port  627  is positioned between the retracted sharpened distal end of the lancet  636  and the entrance to the sample flow channels  631 ,  634 . The membrane  635  facilitates the blood sample flow through the sample flow channels  629 ,  632  by restricting the blood from flowing into the area  636  surrounding the distal end of the lancet  637 . The blood thus flows preferentially into the sample reservoir. In an embodiment, the membrane  635  is treated to have a hydrophobic characteristic. In another embodiment, the membrane  635  is made of polymer-based film  638  that has been coated with a silicone-based gel  639 . 
     For example, the membrane structure may comprise a polymer-based film  638  composed of polyethylene terephthalate, such as the film sold under the trademark MYLAR. The membrane structure may further comprise a thin coating of a silicone-based gel  639  such as the gel sold under the trademark SYLGARD on at least one surface of the film. The usefulness of such a film is its ability to reseal after the lancet has penetrated it without physically affecting the lancet&#39;s cutting tip and edges. The MYLAR film provides structural stability while the thin SYLGARD silicone laminate is flexible enough to retain its form and close over the hole made in the MYLAR film. Other similar materials fulfilling the structural stability and flexibility roles may be used in the manufacture of the membrane in this embodiment. 
     The membrane  635  operates to allow the sharpened distal end of the lancet  637  to pierce the membrane as the sharpened distal end of the lancet  637  travels into and through the sample input port  627 . In an embodiment, the silicone-based gel  639  of the membrane  635  automatically seals the cut caused by the piercing lancet. Therefore, after an incision is made on a finger of a user, the blood from the incision is prevented from flowing through the membrane  635 , which aids the blood to travel through the primary sample flow channel  629  to accumulate within the sample reservoir. Thus the film prevents any blood from flowing into the lancet device assembly, and blood contamination and loss into the lancet device mechanism cavity are prevented. Even without the resealing layer  639 , the hydrophobic membrane  635  deters the flow of blood across the membrane  635 , resulting in improved flow through the primary sample flow channel  629  and reduced or eliminated flow through the pierced membrane  635 . 
       FIGS. 68-70  illustrate one implementation of a lancet driver  640  at three different points during the use of the lancet driver. In this description of the lancet driver, proximal indicates a position relatively close to the site of attachment of the sampling module; conversely, distal indicates a position relatively far from the site of attachment of the sampling module. The lancet driver has a driver handle body  641  defining a cylindrical well  642  within which is a preload spring  643 . Proximal to the preload spring  643  is a driver sleeve  644 , which closely fits within and is slidably disposed within the well  642 . The driver sleeve  644  defines a cylindrical driver chamber  645  within which is an actuator spring  646 . Proximal to the actuator spring  646  is a plunger sleeve  647 , which closely fits within and is slidably disposed within the driver sleeve  644 . 
     The driver handle body  641  has a distal end  648  defining a threaded passage  649  into which a preload screw  650  fits. The preload screw defines a counterbore  651 . The preload screw  650  has a distal end  652  attached to a preload adjustment knob  653  and a proximal end  654  defining an aperture  655 . The driver sleeve  644  has a distal end  656  attached to a catch fitting  657 . The catch fitting  657  defines a catch hole  658 . The driver sleeve  644  has a proximal end  659  with a sloped ring feature  660  circling the interior surface of the driver sleeve&#39;s proximal end  659 . 
     The lancet driver includes a plunger stem  660  having a proximal end  661  and a distal end  662 . At its distal end  662 , an enlarged plunger head  663  terminates the plunger stem  660 . At its proximal end  661 , the plunger stem  660  is fixed to the plunger tip  667  by adhesively bonding, welding, crimping, or threading into a hole  665  in the plunger tip  667 . A plunger hook  665  is located on the plunger stem  660  between the plunger head  663  and the plunger tip  667 . The plunger head  663  is slidably disposed within the counterbore  651  defined by the preload screw  650 . The plunger stem  660  extends from the plunger head  663 , through the aperture  655  defined by the proximal end  654  of the preload screw, thence through the hole  658  in the catch fitting  657 , to the joint  664  in the plunger tip  667 . For assembly purposes, the plunger base joint  664  may be incorporated into the plunger sleeve  647 , and the plunger stem  660  attached to the plunger base  664  by crimping, swaging, gluing, welding, or some other means. Note that the lancet driver  640  could be replaced with any of the controlled electromagnetic drivers discussed above. 
     The operation of the tissue penetration sampling device may be described as follows, with reference to  FIGS. 63-70 . In operation, a fresh sampling module  590  is removed from the storage cavity  594  and adjusted for the desired depth setting using the multi-position thumbwheel  607 . The sampling module  590  is then placed onto the end of the lancet driver  591 . The preload setting may be checked, but will not change from cycle to cycle once the preferred setting is found; if necessary, the preload setting may be adjusted using the preload adjustment knob  596 . 
     The combined sampling module and lancet driver assembly is then pressed against the user&#39;s finger (or other selected anatomical feature) in a smooth motion until the preset trigger point is reached. The trigger point corresponds to the amount of preload force that needs to be overcome to actuate the driver to drive the lancet towards the skin. The preload screw allows the preload setting to be adjusted by the user such that a consistent, preset (by the user) amount of preload force is applied to the sampling site  597  each time a lancing is performed. 
     When the motion to press the assembly against the user&#39;s finger is begun (see  FIG. 68 ), the plunger hook  665  engages catch fitting  657 , holding the actuator spring  646  in a cocked position while the force against the finger builds as the driver sleeve  644  continues to compress the preload spring  643 . Eventually (see  FIG. 69 ) the sloped back of the plunger hook  665  slides into the hole  655  in the proximal end of the preload screw  654  and disengages from the catch fitting  657 . The plunger sleeve  647  is free to move in a proximal direction once the plunger hook  665  releases, and the plunger sleeve  647  is accelerated by the actuator spring  646  until the plunger tip  667  strikes the enlarged proximal end of the lancet  212 . 
     Upon striking the enlarged proximal end of the lancet  605 , the plunger tip  667  of the actuated lancet driver reversibly engages the enlarged proximal end of the lancet  605 . This may be accomplished by mechanical means, e.g. a fitting attached to the plunger tip  667  that detachably engages a complementary fitting on the enlarged proximal end of the lancet  605 , or the enlarged proximal end of the lancet  605  may be coated with an adhesive that adheres to the plunger tip  667  of the actuated lancet driver. Upon being engaged by the plunger tip  667 , the lancet  600  slides within the lancet guide  606  with the sharpened distal end of the lancet  604  emerging from the housing  601  through the sampling port  603  to create the incision in the user&#39;s finger. 
     At approximately the point where the plunger tip  667  contacts the enlarged proximal end of the lancet  605 , the actuator spring  646  is at its relaxed position, and the plunger tip  667  is traveling at its maximum velocity. During the extension stroke, the actuator spring  646  is being extended and is slowing the plunger tip  667  and lancet  600 . The end of stroke occurs (see  FIG. 70 ) when the enlarged proximal end of the lancet  605  strikes the multi-position thumbwheel  607 . 
     The direction of movement of the lancet  600  is then reversed and the extended actuator spring then quickly retracts the sharpened distal end of the lancet  604  back through the sampling port  603 . At the end of the return stroke, the lancet  600  is stripped from the plunger tip  667  by the return stop  613 . The adhesive adheres to the return stop  613  retaining the lancet in a safe position. 
     As blood seeps from the wound, it fills the sample input port  603  and is drawn by capillary action into the sample reservoir  603 ′. In this embodiment, there is no reduced pressure or vacuum at the wound, i.e. the wound is at ambient air pressure, although embodiments which draw the blood sample by suction, e.g. supplied by a syringe or pump, may be used. The vent  612  allows the capillary action to proceed until the entire chamber is filled, and provides a transfer port for analysis of the blood by other instrumentation. The finger is held against the sample acquisition module until a complete sample is observed in the sample reservoir. 
     As the sampling module  600  is removed from the lancet driver  591 , a latch  614  that is part of the return stop  613  structure engages a sloped ring feature  660  inside the lancet driver  591 . As the lancet driver  591  is removed from the sampling module  600 , the latch forces the return stop  613  to rotate toward the lancet  600 , bending it to lock it in a safe position, and preventing reuse. 
     As the sampling module  600  is removed from the lancet driver  591 , the driver sleeve  644  is forced to slide in the driver handle body  641  by energy stored in the preload spring  643 . The driver sleeve  644 , plunger sleeve  647 , and actuator spring  646  move outward together until the plunger head  663  on the plunger stem  660  contacts the bottom of the counterbore  651  at the proximal end of the preload screw  654 . The preload spring  643  continues to move the driver sleeve  644  outward compressing the actuator spring  646  until the plunger hook  665  passes through the hole  658  in the catch fitting  657 . Eventually the two springs reach equilibrium and the plunger sleeve  647  comes to rest in a cocked position. 
     After the sampling module  600  is removed from the lancet driver  591 , it may be placed in a separate analysis device to obtain blood chemistry readings. In a preferred embodiment, the integrated housing  601  or sample reservoir  603 ′ of the sampling module  600  contains at least one biosensor, which is powered by and/or read by the separate analysis device. In another embodiment, the analysis device performs an optical analysis of the blood sample directly through the clear plastic cover of the sampling module. Alternatively, the blood sample may be transferred from the sampling module into an analysis device for distribution to various analysis processes. 
     Alternate embodiments of the invention offer improved success rates for sampling, which reduces the needless sacrifice of a sample storage reservoir or an analysis module due to inadequate volume fill. Alternate embodiments allow automatic verification that sufficient blood has been collected before signaling the user (e.g. by a signal light or an audible beep) that it is okay to remove the skin from the sampling site. In such alternate embodiments, one or more additional lancet(s) (denoted backup lancets) and/or lancet driver(s) (denoted backup lancet drivers) and/or sample reservoir(s) (denoted backup sample reservoirs) are present with the “primary” sampling module. 
     In one such preferred embodiment, following detection of inadequate blood sample volume (e.g., by light or electronic methods), a backup sampling cycle is initiated automatically. The “backup sampling cycle” includes disconnecting the primary sample reservoir via a simple valving system, bringing the backup components online, lancing of the skin, collection of the blood, and movement of the blood to the backup sample reservoir. 
     Blood flows into the backup sample reservoir until the required volume is obtained. The cycle repeats itself, if necessary, until the correct volume is obtained. Only then is the sample reservoir made available as a source of sampled blood for use in measurements or for other applications. The series of reservoirs and/or lancets and/or lancet drivers may easily be manufactured in the same housing and be transparent to the user. 
     In one embodiment, up to three sample reservoirs (the primary plus two backup) are present in a single sample acquisition module, each connected via a capillary channel/valving system to one or more sampling ports. Another embodiment has four sample reservoirs (the primary plus three backup) present in a single sample acquisition module, each connected via a capillary channel/valving system to one or more sampling ports. With three or four sample reservoirs, at least an 80% sampling success rate can be achieved for some embodiments. 
     Another embodiment includes a miniaturized version of the tissue penetration sampling device. Several of the miniature lancets may be located in a single sampling site, with corresponding sample flow channels to transfer blood to one or more reservoirs. The sample flow channels may optionally have valves for controlling flow of blood. The device may also include one or more sensors, such as the thermal sensors discussed above, for detecting the presence of blood, e.g. to determine if a sufficient quantity of blood has been obtained. In such an embodiment, the disposable sampling module, the lancet driver, and the optional module cartridge will have dimensions no larger than about 150 mm long, 60 mm wide, and 25 mm thick. 
     In other embodiments, the size of the tissue penetration sampling device including the disposable sampling module, the lancet driver, and the optional cartridge will have dimensions no larger than about 100 mm long, about 50 mm wide, and about 20 mm thick, and in still other embodiments no larger than about 70 mm long, about 30 mm wide, and about 10 mm thick. The size of the tissue penetration sampling device including the disposable sampling module, the lancet driver, and the optional cartridge will generally be at least about 10 mm long, about 5 mm wide, and about 2 mm thick. 
     In another miniature embodiment, the dimensions of the lancet driver without the cartridge or sampling module are no larger than about 80 mm long, 10 mm wide, and 10 mm thick, or specifically no larger than about 50 mm long, 7 mm wide, and 7 mm thick, or even more specifically no larger than about 15 mm long, 5 mm wide, and 3 mm thick; dimensions of the lancet driver without the cartridge or sampling module are generally at least about 1 mm long, 0.1 mm wide, and 0.1 mm thick, or specifically at least about 2 mm long, 0.2 mm wide, and 0.2 mm thick, or more specifically at least about 4 mm long, 0.4 mm wide, and 0.4 mm thick. 
     In yet another miniature embodiment, dimensions of the miniature sampling module without the lancet driver or cartridge are no larger than about 15 mm long, about 10 mm wide, and about 10 mm thick, or no larger than about 10 mm long, about 7 mm wide, and about 7 mm thick, or no larger than about 5 mm long, about 3 mm wide, and about 2 mm thick; dimensions of the miniature sampling module without the lancet driver or cartridge are generally at least about 1 mm long, 0.1 mm wide, and 0.1 mm thick, specifically at least about 2 mm long, 0.2 mm wide, and 0.2 mm thick, or more specifically at least about 4 mm long, 0.4 mm wide, and 0.4 mm thick. 
     In another embodiment, the miniaturized sampling module and the lancet driver form a single unit having a shared housing, and the combined sample acquisition module/lancet driver unit is disposable. Such a combined unit is no larger than about 80 mm long, about 30 mm wide, and about 10 mm thick, specifically no larger than about 50 mm long, about 20 mm wide, and about 5 mm thick, more specifically, no larger than about 20 mm long, about 5 mm wide, and about 3 mm thick; the combined unit is generally at least about 2 mm long, about 0.3 mm wide, and about 0.2 mm thick, specifically at least about 4 mm long, 0.6 mm wide, and 0.4 mm thick, more specifically, at least about 8 mm long, 1 mm wide, and 0.8 mm thick. 
     Referring to  FIG. 71 , another embodiment of a tissue penetration sampling device is shown, incorporating a disposable sampling module  608  cartridge and analyzer device  669  is shown. The analyzer device  669  includes a deck  670  having a lid  671  attached to the deck by hinges along the rear edge of the system  672 . A readout display  673  on the lid  671  functions to give the user information about the status of the analyzer device  669  and/or the sampling module cartridge  668 , or to give readout of a blood test. The analyzer device  669  has several function buttons  674  for controlling function of the analyzer device  669  or for inputting information into the reader device  669 . Alternatively, the reader device may have a touch-sensitive screen, an optical scanner, or other input means known in the art. 
     An analyzer device with an optical scanner may be particularly useful in a clinical setting, where patient information may be recorded using scan codes on patients&#39; wristbands or files. The analyzer reader device may have a memory, enabling the analyzer device to store results of many recent tests. The analyzer device may also have a clock and calendar function, enabling the results of tests stored in the memory to be time and date-stamped. A computer interface  675  enables records in memory to be exported to a computer. The analyzer device  669  has a chamber located between the deck  670  and the lid  671 , which closely accommodates a sampling module cartridge  668 . Raising the lid  671 , allowing a sampling module cartridge  668  to be inserted or removed, accesses the chamber. 
       FIG. 72  is an illustration showing some of the features of an embodiment of a sampling module cartridge. The sampling module cartridge  668  has a housing having an orientation sensitive contact interface for mating with a complementary surface on the analyzer device. The contact interface functions to align the sampling module cartridge with the analyzer device, and also allows the analyzer device to rotate the sampling module cartridge in preparation for a new sampling event. The contact interface may take the form of cogs or grooves formed in the housing, which mate with complementary cogs, or grooves in the chamber of the analyzer device. 
     The sampling module cartridge has a plurality of sampling sites  678  on the housing, which are shown as slightly concave depressions near the perimeter of the sampling module cartridge  668 . Each sampling site defines an opening  679  contiguous with a sample input port entering the sampling module. In an alternate embodiment, the sampling sites and sample input ports are located on the edge of the sampling module cartridge. Optical windows  680  allow transmission of light into the sampling module cartridge for the purpose of optically reading test results. Alternatively, sensor connection points allow transmission of test results to the analyzer device via electrical contact. Access ports  681 , if present, allow transmission of force or pressure into the sampling module cartridge from the analyzer device. The access ports may be useful in conjunction with running a calibration test or combining reagents with sampled blood or other bodily fluids. 
     The described features are arranged around the sampling module cartridge, and the sampling module cartridge is radially partitioned into many sampling modules, each sampling module having the components necessary to perform a single blood sampling and testing event. A plurality of sampling modules are present on a sampling module cartridge, generally at least ten sampling modules are present on a single disposable sampling module cartridge; at least about 20, or more on some embodiments, and at least about 34 sampling modules are present on one embodiment, allowing the sampling module cartridge to be maintained in the analyzer device for about a week before replacing with a new sampling module cartridge (assuming five sampling and testing events per day for seven days). With increasing miniaturization, up to about 100, or more preferably up to about 150, sampling modules may be included on a single sampling module cartridge, allowing up to a month between replacements with new sampling module cartridges. It may be necessary for sampling sites to be located in several concentric rings around the sampling module cartridge or otherwise packed onto the housing surface to allow the higher number of sampling modules on a single sampling module cartridge. 
     In other embodiments, the sampling module cartridge may be any other shape which may conveniently be inserted into a analyzer device and which are designed to contain multiple sampling modules, e.g. a square, rectangular, oval, or polygonal shape. Each sampling module is miniaturized, being generally less than about 6.0 cm long by about 1.0 cm wide by about 1.0 cm thick, so that thirty five more or less wedge-shaped sampling modules can fit around a disk having a radius of about 6.0 cm. In some embodiments, the sampling modules can be much smaller, e.g. less than about 3.0 cm long by about 0.5 cm wide by about 0.5 cm thick. 
       FIG. 73  depicts, in a highly schematic way, a single sampling module, positioned within the analyzer device. Of course, it will occur to the person of ordinary skill in the art that the various recited components may be physically arranged in various configurations to yield a functional system.  FIG. 73  depicts some components, which might only be present in alternate embodiments and are not necessarily all present in any single embodiment. The sampling module has a sample input port  682 , which is contiguous with an opening  683  defined by a sampling site  684  on the cartridge housing  685 . A lancet  686  having a lancet tip  687  adjacent to the sample input port  682  is operably maintained within the housing such that the lancet  686  can move to extend the lancet tip  687  through the sample input port  682  to outside of the sampling module cartridge. 
     The lancet  686  also has a lancet head  688  opposite the lancet tip. The lancet  686  driven to move by a lancet driver  689 , which is schematically depicted as a coil around the lancet  686 . The lancet driver  689  optionally is included in the sampling module cartridge as pictured or alternatively is external to the sampling module cartridge. The sampling module may further include a driver port  690  defined by the housing adjacent to the lancet head  688 —the driver port  690  allows an external lancet driver  691  access to the lancet  686 . 
     In embodiments where the lancet driver  689  is in the sampling module cartridge, it may be necessary to have a driver connection point  694  upon the housing accessible to the analyzer device. The driver connection point  694  may be a means of triggering the lancet driver  689  or of supplying motive force to the lancet driver  689 , e.g. an electrical current to an electromechanical lancet driver. Note that any of the drivers discussed above, including controllable drivers, electromechanical drivers, etc., can be substituted for the lancet driver  689  shown. 
     In one embodiment a pierceable membrane  692  is present between the lancet tip  687  and the sample input port  682 , sealing the lancet  686  from any outside contact prior to use. A second membrane  693  may be present adjacent to the lancet head  688  sealing the driver port  690 . The pierceable membrane  692  and the second membrane  693  function to isolate the lancet  686  within the lancet chamber to maintain sterility of the lancet  686  prior to use. During use the lancet tip  687  and the external lancet driver  691  pierce the pierceable membrane  692  and the second membrane  693 , if present respectively. 
     A sample flow channel  695  leads from the sample input port  682  to an analytical region  696 . The analytical region  696  is associated with a sample sensor capable of being read by the analyzer device. If the sample sensor is optical in nature, the sample sensor may include optically transparent windows  697  in the housing above and below the analytical region  696 , allowing a light source in the analyzer device to pass light  698  through the analytical region. An optical sensor  698 ′, e.g. a CMOS array, is present in the analyzer device for sensing the light  699  that has passed through the analytical region  696  and generating a signal to be analyzed by the analyzer device. 
     In a separate embodiment, only one optically transparent window is present, and the opposing side of the analytical region is silvered or otherwise reflectively coated to reflect light back through the analytical region and out the window to be analyzed by the analyzer device. In an alternate embodiment, the sensor is electrochemical  700 , e.g. an enzyme electrode, and includes a means of transmitting an electric current from the sampling module cartridge to the analyzer device, e.g. an electrical contact  701 , or plurality of electrical contacts  701 , on the housing accessible to the analyzer device. 
     In one embodiment, the pierceable membrane  692  may be made of polymer-based film that has been coated with a silicone-based gel. For example, the membrane structure may comprise a polymer-based film composed of polyethylene terephthalate, such as the film sold under the trademark MYLAR®. The membrane structure may further comprise a thin coating of a silicone-based gel such as the gel sold under the trademark SYLGARD® on at least one surface of the film. 
     The usefulness of such a film is its ability to reseal after the lancet tip has penetrated it without physically affecting the lancet&#39;s cutting tip and edges. The MYLAR® film provides structural stability while the thin SYLGARD® silicone laminate is flexible enough to retain its form and close over the hole made in the MYLAR® film. Other similar materials fulfilling the structural stability and flexibility roles may be used in the manufacture of the pierceable membrane in this embodiment. 
     The pierceable membrane  692  operates to allow the lancet tip  687  to pierce the pierceable membrane  692  as the lancet tip  687  travels into and through the sampling port  682 . In the described embodiment, the silicone-based gel of the membrane  692  automatically seals the cut caused by the lancet tip  687 . Therefore, after an incision is made on a finger of a user and the lancet tip  687  is retracted back through the pierceable membrane  692 , the blood from the incision is prevented from flowing through the pierceable membrane  692 , which aids the blood to travel through the sample flow channel  695  to accumulate within the analytical region  696 . 
     Thus the pierceable membrane  692  prevents blood from flowing into the lancet device assembly, and blood contamination and loss into the lancet device mechanism cavity are prevented. In yet another embodiment, used sample input ports are automatically sealed off before going to the next sample acquisition cycle by a simple button mechanism. A similar mechanism seals off a sample input port should sampling be unsuccessful. 
     In an alternate embodiment, a calibrant supply reservoir  702  is also present in each sampling module. The calibrant supply reservoir  702  is filled with a calibrant solution and is in fluid communication with a calibration chamber  703 . The calibration chamber  703  provides a source of a known signal from the sampling module cartridge to be used to validate and quantify the test conducted in the analytical region  696 . As such, the configuration of the calibration chamber  703  closely resembles the analytical region  696 . 
     During use, the calibrant solution is forced from the calibrant supply reservoir  702  into the calibration chamber  703 . The figure depicts a stylized plunger  704  above the calibrant supply reservoir  702  ready to squeeze the calibrant supply reservoir  702 . In practice, a variety of methods of transporting small quantities of fluid are known in the art and can be implemented on the sampling module cartridge. The calibration chamber  703  is associated with a calibrant testing means. 
       FIG. 73  shows two alternate calibrant testing means—optical windows  697  and an electrochemical sensor  676 . In cases where the sampling module is designed to perform several different tests on the blood, both optical and electrochemical testing means may be present. The optical windows  697  allow passage of light  677  from the analyzer device through the calibration chamber  703 , whereupon the light  703 ′ leaving the calibration chamber  703  passes onto an optical sensor  698 ′ to result in a signal in the analyzer device. 
     The electrochemical sensor  676  is capable of generating a signal that is communicated to the analyzer device via, e.g. an electrical contact  704 ′, which is accessible to a contact probe  702 ′ on the analyzer device that can be extended to contact the electrical contact  704 ′. The calibrant solution may be any solution, which, in combination with the calibrant testing means, will provide a suitable signal, which will serve as calibration measurement to the analyzer device. Suitable calibrant solutions are known in the art, e.g. glucose solutions of known concentration. The calibration measurement is used to adjust the results obtained from sample sensor from the analytical region  696 . 
     To maintain small size in some sampling module cartridge embodiments, allowing small quantities of sampled blood to be sufficient, each component of the sampling module must be small, particularly the sample flow channel and the analytical region. The sample flow channel can be less than about 0.5 mm in diameter, specifically less than about 0.3 mm in diameter, more specifically less than about 0.2 mm in diameter, and even more specifically less than about 0.1 mm in diameter. 
     The sample flow channel may generally be at least about 50 micrometers in diameter. The dimensions of the analytical region may be less than about 1 mm by about 1 mm by about 1 mm, specifically less than about 0.6 mm by about 0.6 mm by about 0.4 mm, more specifically less than about 0.4 mm by 0.4 mm by 0.2 mm, and even more specifically less than about 0.2 mm by about 0.2 mm by about 0.1 mm. The analytical region can generally be at least about 100 micrometers by 100 micrometers by 50 micrometers. 
     The sampling module cartridge is able to return a valid testing result with less than about 5 microliters of blood taken from the skin of a patient, specifically less than about 1 microliter, more specifically less than about 0.4 microliters, and even more specifically less than about 0.2 microliters. Generally, at least 0.05 microliters of blood is drawn for a sample. 
     The cartridge housing may be made in a plurality of distinct pieces, which are then assembled to provide the completed housing. The distinct pieces may be manufactured from a wide range of substrate materials. Suitable materials for forming the described apparatus include, but are not limited to, polymeric materials, ceramics (including aluminum oxide and the like), glass, metals, composites, and laminates thereof. Polymeric materials are particularly preferred herein and will typically be organic polymers that are homopolymers or copolymers, naturally occurring or synthetic, crosslinked or uncrosslinked. 
     It is contemplated that the various components and devices described herein, such as sampling module cartridges, sampling modules, housings, etc., may be made from a variety of materials, including materials such as the following: polycarbonates; polyesters, including poly (ethylene terephthalate) and poly(butylene terephthalate); polyamides, (such as nylons); polyethers, including polyformaldehyde and poly (phenylene sulfide); polyimides, such as that manufactured under the trademarks KAPTON (DuPont, Wilmington, Del.) and UPILEX (Ube Industries, Ltd., Japan); polyolefin compounds, including ABS polymers, Kel-F copolymers, poly(methyl methacrylate), poly(styrene-butadiene) copolymers, poly(tetrafluoroethylene), poly(ethylenevinyl acetate) copolymers, poly(N-vinylcarbazole) and polystyrene. 
     The various components and devices described herein may also be fabricated from a “composite,” i.e., a composition comprised of unlike materials. The composite may be a block composite, e.g., an A-B-A block composite, an A-B-C block composite, or the like. Alternatively, the composite may be a heterogeneous combination of materials, i.e., in which the materials are distinct from separate phases, or a homogeneous combination of unlike materials. A laminate composite with several different bonded layers of identical or different materials can also be used. 
     Other preferred composite substrates include polymer laminates, polymer-metal laminates, e.g., polymer coated with copper, a ceramic-in-metal or a polymer-in-metal composite. One composite material is a polyimide laminate formed from a first layer of polyimide such as KAPTON polyimide, available from DuPont (Wilmington, Del.), that has been co-extruded with a second, thin layer of a thermal adhesive form of polyimide known as KJ®, also available from DuPont (Wilmington, Del.). 
     Any suitable fabrication method for the various components and devices described herein can be used, including, but not limited to, molding and casting techniques, embossing methods, surface machining techniques, bulk machining techniques, and stamping methods. Further, injection-molding techniques well known in the art may be useful in shaping the materials used to produce sample modules and other components. 
     For some embodiments, the first time a new sampling module cartridge  668  is used, the user removes any outer packaging material from the sampling module cartridge  668  and opens the lid  671  of the analyzer device  669 , exposing the chamber. The sampling module cartridge  668  is slipped into the chamber and the lid  671  closed. The patient&#39;s skin is positioned upon the sampling site  678  and the integrated process of lancing the skin, collecting the blood sample, and testing the blood sample is initiated, e.g. by pressing a function button  674  to cause the lancet driver to be triggered. The patient&#39;s skin is maintained in position upon the sampling site  678 , adjacent the sample input port  682 , until an adequate volume of blood has been collected, whereupon the system may emit a signal (e.g. an audible beep) that the patient&#39;s skin may be lifted from the sampling site  678 . 
     When the testing of the sample is complete, the analyzer device  669  automatically reads the results from the sampling module cartridge  668  and reports the results on the readout display  673 . The analyzer device  669  may also store the result in memory for later downloading to a computer system. The sampling module cartridge  668  may then automatically be advanced to bring the next sampling module inline for the next use. Each successive time the system is used (optionally until the sampling module cartridge  668  is used up), the patient&#39;s skin may be placed upon the sampling site  678  of the (already installed) sampling module cartridge  668 , thus simplifying the process of blood sampling and testing. 
     A method of providing more convenient blood sampling, wherein a series of blood samples may be collected and tested using a single disposable sampling module cartridge which is designed to couple to an analyzer device is described. Embodiments of the sampling module cartridge include a plurality of sampling modules. Each sampling module can be adapted to perform a single blood sampling cycle and is functionally arranged within the sampling module cartridge to allow a new sampling module to be brought online after a blood sampling cycle is completed. 
     Each blood sampling cycle may include lancing of a patient&#39;s skin, collection of a blood sample, and testing of the blood sample. The blood sampling cycle may also include reading of information about the blood sample by the analyzer device, display and/or storage of test results by the analyzer device, and/or automatically advancing the sampling module cartridge to bring a new sampling module online and ready for the next blood sampling cycle to begin. 
     A method embodiment starts with coupling of the sampling module cartridge and analyzer device and then initiating a blood sampling cycle. Upon completion of the blood sampling cycle, the sampling module cartridge is advanced to bring a fresh, unused sampling module online, ready to perform another blood sampling cycle. Generally, at least ten sampling modules are present, allowing the sampling module cartridge to be advanced nine times after the initial blood sampling cycle. 
     In some embodiments, more sampling modules are present and the sampling module cartridge may be advanced about 19 times, and about 34 times in some embodiments, allowing about 19 or about 34 blood sampling cycles, respectively, after the initial blood sampling cycle. After a series of blood sampling cycles has been performed and substantially all (i.e. more than about 80%) of the sampling modules have been used, the sampling module cartridge is decoupled from the analyzer device and discarded, leaving the analyzer device ready to be coupled with a new sampling module cartridge. 
     Referring to  FIGS. 74-76 , a tissue penetration sampling device  180  is shown with the controllable driver  179  of  FIG. 20  coupled to a sampling module cartridge  705  and disposed within a driver housing  706 . A ratchet drive mechanism  707  is secured to the driver housing  706 , coupled to the sampling module cartridge  705  and configured to advance a sampling module belt  708  within the sampling module cartridge  705  so as to allow sequential use of each sampling module  709  in the sampling module belt  708 . The ratchet drive mechanism  707  has a drive wheel  711  configured to engage the sampling modules  709  of the sampling module belt  708 . The drive wheel  711  is coupled to an actuation lever  712  that advances the drive wheel  711  in increments of the width of a single sampling module  709 . A T-slot drive coupler  713  is secured to the elongated coupler shaft  184 . 
     A sampling module  709  is loaded and ready for use with the drive head  198  of the lancet  183  of the sampling module  709  loaded in the T-slot  714  of the drive coupler  713 . A sampling site  715  is disposed at the distal end  716  of the sampling module  709  disposed about a lancet exit port  717 . The distal end  716  of the sampling module  709  is exposed in a module window  718 , which is an opening in a cartridge cover  721  of the sampling module cartridge  705 . This allows the distal end  716  of the sampling module  709  loaded for use to be exposed to avoid contamination of the cartridge cover  721  with blood from the lancing process. 
     A reader module  722  is disposed over a distal portion of the sampling module  709  that is loaded in the drive coupler  713  for use and has two contact brushes  724  that are configured to align and make electrical contact with sensor contacts  725  of the sampling module  709  as shown in  FIG. 77 . With electrical contact between the sensor contacts  725  and contact brushes  724 , the processor  193  of the controllable driver  179  can read a signal from an analytical region  726  of the sampling module  709  after a lancing cycle is complete and a blood sample enters the analytical region  726  of the sampling module  709 . The contact brushes  724  can have any suitable configuration that will allow the sampling module belt  708  to pass laterally beneath the contact brushes  724  and reliably make electrical contact with the sampling module  709  loaded in the drive coupler  713  and ready for use. A spring loaded conductive ball bearing is one example of a contact brush  724  that could be used. A resilient conductive strip shaped to press against the inside surface of the flexible polymer sheet  727  along the sensor contact region  728  of the sampling module  709  is another embodiment of a contact brush  724 . 
     The sampling module cartridge  705  has a supply canister  729  and a receptacle canister  730 . The unused sampling modules of the sampling module belt  708  are disposed within the supply canister  729  and the sampling modules of the sampling module belt  708  that have been used are advanced serially after use into the receptacle canister  730 . 
       FIG. 77  is a perspective view of a section of the sampling module belt  708  shown in the sampling module cartridge  705  in  FIG. 74 . The sampling module belt  708  has a plurality of sampling modules  709  connected in series by a sheet of flexible polymer  727 . The sampling module belt  708  shown in  FIG. 77  is formed from a plurality of sampling module body portions  731  that are disposed laterally adjacent each other and connected and sealed by a single sheet of flexible polymer  727 . The flexible polymer sheet  727  can optionally have sensor contacts  725 , flexible electrical conductors  732 , sample sensors  733  or any combination of these elements formed on the inside surface  734  of the flexible polymer sheet  727 . These electrical, optical or chemical elements can be formed by a variety of methods including vapor deposition and the like. 
     The proximal portion  735  of the flexible polymer sheet  727  has been folded over on itself in order to expose the sensor contacts  725  to the outside surface of the sampling module  709 . This makes electrical contact between the contact brushes  724  of the reader module  722  and the sensor contacts  725  easier to establish as the sampling modules  709  are advanced and loaded into position with the drive coupler  713  of the controllable driver  179  ready for use. The flexible polymer sheet  727  can be secured to the sampling module body portion  731  by adhesive bonding, solvent bonding, ultrasonic thermal bonding or any other suitable method. 
       FIG. 78  shows a perspective view of a single sampling module  709  of the sampling module belt  708  of  FIG. 77  during the assembly phase of the sampling module  709 . The proximal portion  735  of the flexible polymer sheet  727  is being folded over on itself as shown in order to expose the sensor contacts  725  on the inside surface of the flexible polymer sheet  727 .  FIG. 79  is a bottom view of a section of the flexible polymer sheet  727  of the sampling module  709  of  FIG. 78  illustrating the sensor contacts  725 , flexible conductors  732  and sample sensors  733  deposited on the bottom surface of the flexible polymer sheet  727 . 
     A lancet  183  is shown disposed within the lancet channel  736  of the sampling module  709  of  FIG. 78  as well as within the lancet channels  736  of the sampling modules  709  of the sampling module belt  708  of  FIG. 77 . The lancet  183  has a tip  196  and a shaft portion  201  and a drive head  198 . The shaft portion  201  of the lancet slides within the lancet channel  736  of the sampling module  709  and the drive head  198  of the lancet  183  has clearance to move in a proximal and distal direction within the drive head slot  737  of the sampling module  709 . Disposed adjacent the drive head slot  737  and at least partially forming the drive head slot are a first protective strut  737 ′ and a second protective strut  737 ″ that are elongated and extend substantially parallel to the lancet  183 . 
     In one lancet  183  embodiment, the drive head  198  of the lancet  183  can have a width of about 0.9 to about 1.1 mm. The thickness of the drive head  198  of the lancet  183  can be about 0.4 to about 0.6 mm. The drive head slot  714  of the sampling module  709  should have a width that allows the drive head  198  to move freely within the drive head slot  714 . The shaft portion  201  of the lancet  183  can have a transverse dimension of about 50 μm to about 1000 μm. Typically, the shaft portion  201  of the lancet  183  has a round transverse cross section, however, other configurations are contemplated. 
     The sampling module body portions  731  and the sheet of flexible polymer  727  can both be made of polymethylmethacrylate (PMMA), or any other suitable polymer, such as those discussed above. The dimensions of a typical sampling module body portion  731  can be about 14 to about 18 mm in length, about 4 to about 5 mm in width, and about 1.5 to about 2.5 mm in thickness. In other embodiments, the length of the sample module body portion can be about 0.5 to about 2.0 inch and the transverse dimension can be about 0.1 to about 0.5 inch. The thickness of the flexible polymer sheet  727  can be about 100 to about 150 microns. The distance between adjacent sampling modules  709  in the sampling module belt  708  can vary from about 0.1 mm to about 0.3 mm, and in some embodiments, from about 0.2 to about 0.6. 
       FIGS. 80 and 81  show a perspective view of the body portion  731  of the sampling module  709  of  FIG. 77  without the flexible polymer cover sheet  727  or lancet  183  shown for purposes of illustration.  FIG. 81  is an enlarged view of a portion of the body portion  731  of the sampling module  709  of  FIG. 80  illustrating the sampling site  715 , sample input cavity  715 ′, sample input port  741 , sample flow channel  742 , analytical region  743 , control chamber  744 , vent  762 , lancet channel  736 , lancet channel stopping structures  747  and  748  and lancet guides  749 - 751  of the sampling module  709 . 
     The lancet channel  736  has a proximal end  752  and a distal end  753  and includes a series of lancet bearing guide portions  749 - 751  and sample flow stopping structures  747 - 748 . The lancet guides  749 - 751  may be configured to fit closely with the shaft of the lancet  183  and confine the lancet  183  to substantially axial movement. At the distal end  753  of the lancet channel  736  the distal-most lancet guide portion  749  is disposed adjacent the sample input port  741  and includes at its distal-most extremity, the lancet exit port  754  which is disposed adjacent the sample input cavity  715 ′. The sample input cavity can have a transverse dimension, depth or both, of about 2 to 5 times the transverse dimension of the lancet  183 , or about 0.2 to about 2 mm, specifically, about 0.4 to about 1.5 mm, and more specifically, about 0.5 to about 1.0 mm. The distal-most lancet guide  749  can have inner transverse dimensions of about 300 to about 350 microns in width and about 300 to about 350 microns in depth. Proximal of the distal-most lancet guide portion  749  is a distal sample flow stop  747  that includes a chamber adjacent the distal-most lancet  749 . The chamber has a transverse dimension that is significantly larger than the transverse dimension of the distal-most lancet guide  749 . The chamber can have a width of about 600 to about 800 microns, and a depth of about 400 to about 600 microns and a length of about 2000 to about 2200 microns. The rapid transition of transverse dimension and cross sectional area between the distal-most lancet bearing guide  749  and the distal sample flow stop  747  interrupts the capillary action that draws a fluid sample through the sample input cavity  715 ′ and into the lancet channel  736 . 
     A center lancet bearing guide  750  is disposed proximal of the distal lancet channel stop  747  and can have dimensions similar to those of the distal-most lancet bearing guide  749 . Proximal of the center lancet guide  750  is a proximal lancet channel stop  748  with a chamber. The dimensions of the proximal lancet channel stop can be the same or similar to those of the distal lancet channel stop  747 . The proximal lancet channel stop  748  can have a width of about 600 to about 800 microns, and a depth of about 400 to about 600 microns and a length of about 2800 to about 3000 microns. Proximal of the proximal lancet channel stop  748  is a proximal lancet guide  751 . The proximal lancet guide  751  can dimensions similar to those of the other lancet guide  749  and  750  portions with inner transverse dimensions of about 300 to about 350 microns in width and about 300 to about 350 microns in depth. Typically, the transverse dimension of the lancet guides  749 - 751  are about 10 percent larger than the transverse dimension of the shaft portion  201  of the lancet  183  that the lancet guides  749 - 751  are configured to guide. 
     A proximal fracturable seal (not shown) can be positioned between the proximal lancet guide  751  and the shaft portion  201  of the lancet  183  that seals the chamber of the proximal lancet channel stop  748  from the outside environment. The fracturable seal seals the chamber of the proximal lancet channel stop  748  and other interior portions of the sample chamber from the outside environment when the sampling module  709  is stored for use. The fracturable seal remains intact until the lancet  183  is driven distally during a lancet cycle at which point the seal is broken and the sterile interior portion of the sample chamber is exposed and ready to accept input of a liquid sample, such as a sample of blood. A distal fracturable seal (not shown) can be disposed between the lancet  183  and the distal-most lancet guide  749  of the sampling module  709  to seal the distal end  753  of the lancet channel  736  and sample input port  741  to maintain sterility of the interior portion of the sampling module  709  until the lancet  183  is driven forward during a lancing cycle. 
     Adjacent the lancet exit port  754  within the sample input cavity  715 ′ is the sample input port  741  that is configured to accept a fluid sample that emanates into the sample input cavity  715 ′ from target tissue  233  at a lancing site after a lancing cycle. The dimensions of the sample input port  741  can a depth of about 60 to about 70 microns, a width of about 400 to about 600 microns. The sample input cavity can have a transverse dimension of about 2 to about 5 times the transverse dimension of the lancet  183 , or about 400 to about 1000 microns. The sample input cavity serves to accept a fluid sample as it emanates from lanced tissue and direct the fluid sample to the sample input port  741  and thereafter the sample flow channel  742 . The sample flow channel  742  is disposed between and in fluid communication with the sample input port  741  and the analytical region  743 . The transverse dimensions of the sample flow channel  742  can be the same as the transverse dimensions of the sample input port  741  with a depth of about 60 to about 70 microns, a width of about 400 to about 600 microns. The length of the sample flow channel  742  can be about 900 to about 1100 microns. Thus, in use, target tissue is disposed on the sampling site  715  and a lancing cycle initiated. Once the target tissue  233  has been lanced and the sample begins to flow therefrom, the sample enters the sample input cavity  715 ′ and then the sample input port  741 . The sample input cavity  715 ′ may be sized and configured to facilitate sampling success by applying pressure to a perimeter of target tissue  233  before, during and after the lancing cycle and hold the wound track open after the lancing cycle to allow blood or other fluid to flow from the wound track and into the sample input cavity  715 ′. From the sample input port  741 , the sample in then drawn by capillary or other forces through the sample flow channel  742  and into the analytical region  743  and ultimately into the control chamber  744 . The control chamber  744  may be used to provide indirect confirmation of a complete fill of the analytical region  743  by a sample fluid. If a fluid sample has been detected in the control chamber  744 , this confirms that the sample has completely filled the analytical region  743 . Thus, sample detectors may be positioned within the control chamber  744  to confirm filling of the analytical region  743 . 
     The analytical region  743  is disposed between and in fluid communication with the sample flow channel  742  and the control chamber  744 . The analytical region  743  can have a depth of about 60 to about 70 microns, a width of about 900 to about 1100 microns and a length of about 5 to about 6 mm. A typical volume for the analytical region  743  can be about 380 to about 400 nanoliters. The control chamber  744  is disposed adjacent to and proximal of the analytical region  743  and can have a transverse dimension or diameter of about 900 to about 1100 microns and a depth of about 60 to about 70 microns. 
     The control chamber  744  is vented to the chamber of the proximal lancet channel stop  748  by a vent that is disposed between and in fluid communication with the control chamber  744  and the chamber of the proximal lancet channel stop  748 . Vent  762  can have transverse dimensions that are the same or similar to those of the sample flow channel  742  disposed between the analytical region  743  and the sample input port  741 . Any of the interior surfaces of the sample input port  741 , sample flow channels  742  and  762 , analytical region  743 , vents  745  or control chamber  744  can be coated with a coating that promotes capillary action. A hydrophilic coating such as a detergent is an example of such a coating. 
     The analytical region  743  accommodates a blood sample that travels by capillary action from the sampling site  715  through the sample input cavity  715 ′ and into the sample input port  741 , through the sample flow channel  742  and into the analytical region  743 . The blood can then travel into the control chamber  744 . The control chamber  744  and analytical region  743  are both vented by the vent  762  that allows gases to escape and prevents bubble formation and entrapment of a sample in the analytical region  743  and control chamber  744 . Note that, in addition to capillary action, flow of a blood sample into the analytical region  743  can be facilitated or accomplished by application of vacuum, mechanical pumping or any other suitable method. 
     Once a blood sample is disposed within the analytical region  743 , analytical testing can be performed on the sample with the results transmitted to the processor  193  by electrical conductors  732 , optically or by any other suitable method or means. In some embodiments, it may be desirable to confirm that the blood sample has filled the analytical region  743  and that an appropriate amount of sample is present in the chamber in order to carry out the analysis on the sample. 
     Confirmation of sample arrival in either the analytical region  743  or the control chamber  744  can be achieved visually, through the flexible polymer sheet  727  which can be transparent. However, it may be desirable in some embodiments to use a very small amount of blood sample in order to reduce the pain and discomfort to the patient during the lancing cycle. For sampling module  709  embodiments such as described here, having the sample input cavity  715 ′ and sample input port  741  adjacent the lancet exit port  754  allows the blood sample to be collected from the patient&#39;s skin  233  without the need for moving the sampling module  709  between the lancing cycle and the sample collection process. As such, the user does not need to be able to see the sample in order to have it transferred into the sampling module  709 . Because of this, the position of the sample input cavity  715 ′ and the sample input port  741  adjacent the lancet exit port  754  allows a very small amount of sample to be reliably obtained and tested. 
     Samples on the order of tens of nanoliters, such as about 10 to about 50 nanoliters can be reliably collected and tested with a sampling module  709 . This size of blood sample is too small to see and reliably verify visually. Therefore, it is necessary to have another method to confirm the presence of the blood sample in the analytical region  743 . Sample sensors  733 , such as the thermal sample sensors discussed above can positioned in the analytical region  743  or control chamber  744  to confirm the arrival of an appropriate amount of blood sample. 
     In addition, optical methods, such as spectroscopic analysis of the contents of the analytical region  743  or control chamber  744  could be used to confirm arrival of the blood sample. Other methods such as electrical detection could also be used and these same detection methods can also be disposed anywhere along the sample flow path through the sampling module  709  to confirm the position or progress of the sample (or samples) as it moves along the flow path as indicated by the arrows  763  in  FIG. 81 . The detection methods described above can also be useful for analytical methods requiring an accurate start time. 
     The requirement for having an accurate start time for an analytical method can in turn require rapid filling of an analytical region  743  because many analytical processes begin once the blood sample enters the analytical region  743 . If the analytical region  743  takes too long to fill, the portion of the blood sample that first enters the analytical region  743  will have been tested for a longer time that the last portion of the sample to enter the analytical region  743  which can result in inaccurate results. Therefore, it may be desirable in these circumstances to have the blood sample flow first to a reservoir, filling the reservoir, and then have the sample rapidly flow all at once from the reservoir into the analytical region  743 . 
     In one embodiment of the sampling module  709 , the analytical region  743  can have a transverse cross section that is substantially greater than a transverse cross section of the control chamber  744 . The change in transverse cross section can be accomplished by restrictions in the lateral transverse dimension of the control chamber  744  versus the analytical region  743 , by step decreases in the depth of the control chamber  744 , or any other suitable method. Such a step between the analytical region  743  and the control chamber  744  is shown in  FIG. 81 . In such an embodiment, the analytical region  743  can behave as a sample reservoir and the control chamber  744  as an analytical region that requires rapid or nearly instantaneous filling in order to have a consistent analysis start time. The analytical region  743  fills by a flow of sample from the sample flow channel  742  until the analytical region is full and the sample reaches the step decrease in chamber depth at the boundary with the control chamber  744 . Once the sample reaches the step decrease in cross sectional area of the control chamber  744 , the sample then rapidly fills the control chamber  744  by virtue of the enhanced capillary action of the reduced cross sectional area of the control chamber  744 . The rapid filling of the control chamber allows any analytical process initiated by the presence of sample to be carried out in the control chamber  744  with a reliable start time for the analytical process for the entire sample of the control chamber  744 . 
     Filling by capillary force is passive. It can also be useful for some types of analytical testing to discard the first portion of a sample that enters the sampling module  709 , such as the case where there may be interstitial fluid contamination of the first portion of the sample. Such a contaminated portion of a sample can be discarded by having a blind channel or reservoir that draws the sample by capillary action into a side sample flow channel (not shown) until the side sample flow channel or reservoir in fluid communication therewith, is full. The remainder of the sample can then proceed to a sample flow channel adjacent the blind sample flow channel to the analytical region  743 . 
     For some types of analytical testing, it may be advantageous to have multiple analytical regions  743  in a single sampling module  709 . In this way multiple iterations of the same type of analysis could be performed in order to derive some statistical information, e.g. averages, variation or confirmation of a given test or multiple tests measuring various different parameters could be performed in different analytical regions  743  in the same sampling module  709  filled with a blood sample from a single lancing cycle. 
       FIG. 82  is an enlarged elevational view of a portion of an alternative embodiment of a sampling module  766  having a plurality of small volume analytical regions  767 . The small volume analytical regions  767  can have dimensions of about 40 to about 60 microns in width in both directions and a depth that yields a volume for each analytical region  767  of about 1 nanoliter to about 100 nanoliters, specifically about 10 nanoliters to about 50 nanoliters. The array of small volume analytical regions  767  can be filled by capillary action through a sample flow channel  768  that branches at a first branch point  769 , a second branch point  770  and a third branch point  771 . Each small volume analytical region  767  can be used to perform a like analytical test or a variety of different tests can be performed in the various analytical regions  767 . 
     For some analytical tests, the analytical regions  767  must have maintain a very accurate volume, as some of the analytical tests that can be performed on a blood sample are volume dependent. Some analytical testing methods detect glucose levels by measuring the rate or kinetic of glucose consumption. Blood volume required for these tests is on the order of about 1 to about 3 microliters. The kinetic analysis is not sensitive to variations in the volume of the blood sample as it depends on the concentration of glucose in the relatively large volume sample with the concentration of glucose remaining essentially constant throughout the analysis. Because this type of analysis dynamically consumes glucose during the testing, it is not suitable for use with small samples, e.g. samples on the order of tens of nanoliters where the consumption of glucose would alter the concentration of glucose. 
     Another analytical method uses coulomb metric measurement of glucose concentration. This method is accurate if the sample volume is less than about 1 microliter and the volume of the analytical region is precisely controlled. The accuracy and the speed of the method is dependent on the small and precisely known volume of the analytical region  767  because the rate of the analysis is volume dependent and large volumes slow the reaction time and negatively impact the accuracy of the measurement. 
     Another analytical method uses an optical fluorescence decay measurement that allows very small sample volumes to be analyzed. This method also requires that the volume of the analytical region  767  be precisely controlled. The small volume analytical regions  767  discussed above can meet the criteria of maintaining small accurately controlled volumes when the small volume analytical regions  767  are formed using precision manufacturing techniques. Accurately formed small volume analytical regions  767  can be formed in materials such as PMMA by methods such as molding and stamping. Machining and etching, either by chemical or laser processes can also be used. Vapor deposition and lithography can also be used to achieve the desired results. 
     The sampling modules  709  and  766  discussed above all are directed to embodiments that both house the lancet  183  and have the ability to collect and analyze a sample. In some embodiments of a sampling module, the lancet  183  may be housed and a sample collected in a sample reservoir without any analytical function. In such an embodiment, the analysis of the sample in the sample reservoir may be carried out by transferring the sample from the reservoir to a separate analyzer. In addition, some modules only serve to house a lancet  183  without any sample acquisition capability at all. The body portion  774  of such a lancet module  775  is shown in  FIG. 83 . The lancet module  775  has an outer structure similar to that of the sampling modules  709  and  766  discussed above, and can be made from the same or similar materials. 
     A flexible polymer sheet  727  (not shown) can be used to cover the face of the lancet module  775  and contain the lancet  183  in a lancet channel  776  that extends longitudinally in the lancet module body portion  774 . The flexible sheet of polymer  727  can be from the same material and have the same dimensions as the flexible polymer sheet  727  discussed above. Note that the proximal portion of the flexible polymer sheet  727  need not be folded over on itself because there are no sensor contacts  725  to expose. The flexible polymer sheet  727  in such a lancet module  775  serves only to confine the lancet  183  in the lancet channel  776 . The lancet module  775  can be configured in a lancet module belt, similar to the sampling module belt  708  discussed above with the flexible polymer sheet  727  acting as the belt. A drive head slot  777  is dispose proximal of the lancet channel  776 . 
     With regard to the tissue penetration sampling device  180  of  FIG. 74 , use of the device  180  begins with the loading of a sampling module cartridge  705  into the controllable driver housing  706  so as to couple the cartridge  705  to the controllable driver housing  706  and engage the sampling module belt  708  with the ratchet drive  707  and drive coupler  713  of the controllable driver  179 . The drive coupler  713  can have a T-slot configuration such as shown in  FIGS. 84 and 85 . The distal end of the elongate coupler shaft  184  is secured to the drive coupler  713  which has a main body portion  779 , a first and second guide ramp  780  and  781  and a T-slot  714  disposed within the main body portion  779 . The T-slot  714  is configured to accept the drive head  198  of the lancet  183 . After the sampling module cartridge  705  is loaded into the controllable driver housing  706 , the sampling module belt  708  is advanced laterally until the drive head  198  of a lancet  183  of one of the sampling modules  709  is fed into the drive coupler  713  as shown in  FIGS. 86-88 .  FIGS. 86-88  also illustrate a lancet crimp device  783  that bends the shaft portion  201  of a used lancet  183  that is adjacent to the drive coupler  713 . This prevents the used lancet  183  from moving out through the module body  731  and being reused. 
     As the sampling modules  709  of the sampling module belt  708  are used sequentially, they are advanced laterally one at a time into the receptacle canister  730  where they are stored until the entire sampling module belt  708  is consumed. The receptacle canister  730  can then be properly disposed of in accordance with proper techniques for disposal of blood-contaminated waste. The sampling module cartridge  705  allows the user to perform multiple testing operations conveniently without being unnecessarily exposed to blood waste products and need only dispose of one cartridge after many uses instead of having to dispose of a contaminated lancet  183  or module  709  after each use. 
       FIGS. 89 and 90  illustrate alternative embodiments of sampling module cartridges.  FIG. 89  shows a sampling module cartridge  784  in a carousel configuration with adjacent sampling modules  785  connected rigidly and with sensor contacts  786  from the analytical regions of the various sampling modules  785  disposed near an inner radius  787  of the carousel. The sampling modules  785  of the sampling module cartridge  784  are advanced through a drive coupler  713  but in a circular as opposed to a linear fashion. 
       FIG. 90  illustrates a block of sampling modules  788  in a four by eight matrix. The drive head  198  of the lancets  183  of the sampling modules  789  shown in  FIG. 90  are engaged and driven using a different method from that of the drive coupler  713  discussed above. The drive heads  198  of the lancets  183  have an adhesive coating  790  that mates with and secures to the drive coupler  791  of the lancet driver  179 , which can be any of the drivers, including controllable drivers, discussed above. 
     The distal end  792  of the drive coupler  791  contacts and sticks to the adhesive  790  of proximal surface of the drive head  198  of the lancet  183  during the beginning of the lancet cycle. The driver coupler  791  pushes the lancet  183  into the target tissue  237  to a desired depth of penetration and stops. The drive coupler  791  then retracts the lancet  183  from the tissue  233  using the adhesive contact between the proximal surface of the drive head  198  of the lancet  183  and distal end surface of the drive coupler  791 , which is shaped to mate with the proximal surface. 
     At the top of the retraction stroke, a pair of hooked members  793  which are secured to the sampling module  789  engage the proximal surface of the drive head  198  and prevent any further retrograde motion by the drive head  198  and lancet  183 . As a result, the drive coupler  791  breaks the adhesive bond with the drive head  198  and can then be advanced by an indexing operation to the next sampling module  789  to be used. 
       FIG. 91  is a side view of an alternative embodiment of a drive coupler  796  having a lateral slot  797  configured to accept the L-shaped drive head  798  of the lancet  799  that is disposed within a lancet module  800  and shown with the L-shaped drive head  798  loaded in the lateral slot  797 .  FIG. 92  is an exploded view of the drive coupler  796 , lancet  799  with L-shaped drive head  798  and lancet module  800  of  FIG. 91 . This type of drive coupler  796  and drive head  798  arrangements could be substituted for the configuration discussed above with regard to  FIGS. 84-88 . The L-shaped embodiment of the drive head  798  may be a less expensive option for producing a coupling arrangement that allows serial advancement of a sampling module belt or lancet module belt through the drive coupler  796  of a lancet driver, such as a controllable lancet driver  179 . 
     For some embodiments of multiple lancing devices  180 , it may be desirable to have a high capacity-lancing device that does not require a lancet module  775  in order to house the lancets  183  stored in a cartridge. Eliminating the lancet modules  775  from a multiple lancet device  180  allows for a higher capacity cartridge because the volume of the cartridge is not taken up with the bulk of multiple modules  775 .  FIGS. 93-96  illustrate a high capacity lancet cartridge coupled to a belt advance mechanism  804 . The belt advance mechanism  804  is secured to a controlled driver  179  housing which contains a controlled electromagnetic driver. 
     The lancet cartridge  803  has a supply canister  805  and a receptacle canister  806 . A lancet belt  807  is disposed within the supply canister  805 . The lancet belt  807  contains multiple sterile lancets  183  with the shaft portion  201  of the lancets  183  disposed between the adhesive surface  808  of a first carrier tape  809  and the adhesive surface  810  of a second carrier tape  811  with the adhesive surfaces  808  and  810  pressed together around the shaft portion  201  of the lancets  183  to hold them securely in the lancet belt  807 . The lancets  183  have drive heads  198  which are configured to be laterally engaged with a drive coupler  713 , which is secured to an elongate coupler shaft  184  of the controllable driver  179 . 
     The belt advance mechanism  804  includes a first cog roller  814  and a second cog roller  815  that have synchronized rotational motion and are advanced in unison in an incremental indexed motion. The indexed motion of the first and second cog rollers  814  and  815  advances the lancet belt  807  in units of distance equal to the distance between the lancets  183  disposed in the lancet belt  807 . The belt advance mechanism  804  also includes a first take-up roller  816  and a second take-up roller  817  that are configured to take up slack in the first and second carrier tapes  809  and  811  respectively. 
     When a lancet belt cartridge  803  is loaded in the belt advance mechanism  804 , a lead portion  818  of the first carrier tape  809  is disposed between a first cog roller  814  and a second cog roller  815  of the belt advance mechanism  804 . The lead portion  818  of the first carrier tape  809  wraps around the outer surface  819  of the first turning roller  827 , and again engages roller  814  with the cogs  820  of the first cog roller  814  engaged with mating holes  821  in the first carrier tape  809 . The lead portion  818  of the first carrier tape  809  is then secured to a first take-up roller  816 . A lead portion  822  of the second carrier tape  811  is also disposed between the first cog roller  814  and second cog roller  815  and is wrapped around an outer surface  823  of the second turning roller  828 , and again engages roller  815  with the cogs  826 ′ of the second cog roller  815  engaged in with mating holes  825  of the second carrier tape  811 . The lead portion  822  of the second carrier tape  811  is thereafter secured to a second take-up roller  817 . 
     As the first and second cog rollers  814  and  815  are advanced, the turning rollers  827  and  828  peel the first and second carrier tapes  809  and  811  apart and expose a lancet  183 . The added length or slack of the portions of the first and second carrier tapes  809  and  811  produced from the advancement of the first and second cog rollers  814  and  815  is taken up by the first and second take-up rollers  816  and  817 . As a lancet  183  is peeled out of the first and second carrier tapes  809  and  811 , the exposed lancet  183  is captured by a lancet guide wheel  826 ′ of the belt advance mechanism  804 , shown in  FIG. 96 , which is synchronized with the first and second cog rollers  814  and  815 . The lancet guide wheel  826 ′ then advances the lancet  183  laterally until the drive head  198  of the lancet  183  is loaded into the drive coupler  713  of the controllable driver  179 . The controllable driver  179  can then be activated driving the lancet  183  into the target tissue  233  and retracted to complete the lancing cycle. 
     Once the lancing cycle is complete, the belt advance mechanism  804  can once again be activated which rotates the lancet guide wheel  826  and advances the used lancet  183  laterally and into the receptacle canister  806 . At the same time, a new unused lancet  183  is loaded into the drive coupler  713  and readied for the next lancing cycle. This repeating sequential use of the multiple lancing device  180  continues until all lancets  183  in the lancet belt  807  have been used and disposed of in the receptacle canister  806 . After the last lancet  183  has been consumed, the lancet belt cartridge  803  can then be removed and disposed of without exposing the user to any blood contaminated materials. The belt advance mechanism  804  can be activated by a variety of methods, including a motorized drive or a manually operated thumbwheel which is coupled to the first and second cog rollers  814  and  815  and lancet guide wheel  826 . 
     Although discussion of the devices described herein has been directed primarily to substantially painless methods and devices for access to capillary blood of a patient, there are many other uses for the devices and methods. For example, the tissue penetration devices discussed herein could be used for substantially painless delivery of small amounts of drugs, or other bioactive agents such as gene therapy agents, vectors, radioactive sources etc. As such, it is contemplated that the tissue penetration devices and lancet devices discussed herein could be used to delivery agents to positions within a patient&#39;s body as well as taking materials from a patient&#39;s body such as blood, lymph fluid, spinal fluid and the like. Drugs delivered may include analgesics that would further reduce the pain perceived by the patient upon penetration of the patient&#39;s body tissue, as well as anticoagulants that may facilitate the successful acquisition of a blood sample upon penetration of the patient&#39;s tissue. 
     Referring to  FIGS. 97-101 , a device for injecting a drug or other useful material into the tissue of a patient is illustrated. The ability to localize an injection or vaccine to a specific site within a tissue, layers of tissue or organ within the body can be important. For example, epithelial tumors can be treated by injection of antigens, cytokine, or colony stimulating factor by hypodermic needle or high-pressure injection sufficient for the antigen to enter at least the epidermis or the dermis of a patient. Often, the efficacy of a drug or combination drug therapy depends on targeted delivery to localized areas thus affecting treatment outcome. 
     The ability to accurately deliver drugs or vaccinations to a specific depth within the skin or tissue layer may avoid wastage of expensive drug therapies therefore impacting cost effectiveness of a particular treatment. In addition, the ability to deliver a drug or other agent to a precise depth can be a clear advantage where the outcome of treatment depends on precise localized drug delivery (such as with the treatment of intralesional immunotherapy). Also, rapid insertion velocity of a hypodermic needle to a precise predetermined depth in a patient&#39;s skin is expected to reduce pain of insertion of the needle into the skin. Rapid insertion and penetration depth of a hypodermic needle, or any other suitable elongated delivery device suitable for penetrating tissue, can be accurately controlled by virtue of a position feedback loop of a controllable driver coupled to the hypodermic needle. 
       FIG. 97  illustrates  901  distal end  901  of a hypodermic needle  902  being driven into layers of skin tissue  903  by an electromagnetic controllable driver  904 . The electromagnetic controllable driver  904  of  FIG. 79  can have any suitable configuration, such as the configuration of electromagnetic controllable drivers discussed above. The layers of skin  903  being penetrated include the stratum corneum  905 , the stratum lucidum  906 , the stratum granulosum  907 , the stratum spinosum  908 , the stratum basale  909  and the dermis  911 . The thickness of the stratum corneum  905  is typically about 300 micrometers in thickness. The portion of the epidermis excluding the stratum corneum  905  includes the stratum lucidum  906 , stratum granulosum  907 , and stratum basale can be about 200 micrometers in thickness. The dermis can be about 1000 micrometers in thickness. In  FIG. 97 , an outlet port  912  of the hypodermic needle  902  is shown disposed approximately in the stratum spinosum  908  layer of the skin  903  injecting an agent  913  into the stratum spinosum  908 . 
       FIGS. 98-101  illustrate an agent injection module  915  including an injection member  916 , that includes a collapsible canister  917  and the hypodermic needle  902 , that may be driven or actuated by a controllable driver, such as any of the controllable drivers discussed above, to drive the hypodermic needle into the skin  903  for injection of drugs, vaccines or the like. The agent injection module  915  has a reservoir, which can be in the form of the collapsible canister  917  having a main chamber  918 , such as shown in  FIG. 98 , for the drug or vaccine  913  to be injected. A cassette of a plurality of agent injection modules  915  (not shown) may provide a series of metered doses for long-term medication needs. Such a cassette may be configured similarly to the module cassettes discussed above. Agent injection modules  915  and needles  902  may be disposable, avoiding biohazard concerns from unspent drug or used hypodermic needles  902 . The geometry of the cutting facets  921  of the hypodermic needle shown in  FIG. 79 , may be the same or similar to the geometry of the cutting facets of the lancet  183  discussed above. 
     Inherent in the position and velocity control system of some embodiments of a controllable driver is the ability to precisely determine the position or penetration depth of the hypodermic needle  902  relative to the controllable driver or layers of target tissue or skin  903  being penetrated. For embodiments of controllable drivers that use optical encoders for position sensors, such as an Agilent HEDS 9200 series, and using a four edge detection algorithm, it is possible to achieve an in plane spatial resolution of +/−17 μm in depth. If a total tissue penetration stroke is about 3 mm in length, such as might be used for intradermal or subcutaneous injection, a total of 88 position points can be resolved along the penetration stroke. A spatial resolution this fine allows precise placement of a distal tip  901  or outlet port  912  of the hypodermic needle  902  with respect to the layers of the skin  903  during delivery of the agent or drug  913 . In some embodiments, a displacement accuracy of better than about 200 microns can be achieved, in others a displacement accuracy of better than about 40 microns can be achieved. 
     The agent injection module  915  includes the injection member  916  which includes the hypodermic needle  902  and drug reservoir or collapsible canister  917 , which may couple to an elongated coupler shaft  184  via a drive coupler  185  as shown. The hypodermic needle  902  can be driven to a desired penetration depth, and then the drug or other agent  913 , such as a vaccine, is passed into an inlet port  922  of the needle  902  through a central lumen  923  of the hypodermic needle  902  as shown by arrow  924 , shown in  FIG. 98 , and out of the outlet port  912  at the distal end  901  of the hypodermic needle  902 , shown in  FIG. 97 . 
     Drug or agent delivery can occur at the point of maximum penetration, or following retraction of the hypodermic needle  902 . In some embodiments, it may be desirable to deliver the drug or agent  913  during insertion of the hypodermic needle  902 . Drug or agent delivery can continue as the hypodermic needle  902  is being withdrawn (this is commonly the practice during anesthesia in dental work). Alternatively drug delivery can occur while the needle  902  is stationary during any part of the retraction phase. 
     The hollow hypodermic needle  902  is fitted with the collapsible canister  917  containing a drug or other agent  913  to be dispensed. The walls  928  of this collapsible canister  917  can be made of a soft resilient material such as plastic, rubber, or any other suitable material. A distal plate  925  is disposed at the distal end  926  of the collapsible canister is fixed securely to the shaft  927  of the hypodermic needle proximal of the distal tip  901  of the hypodermic needle  902 . The distal plate  925  is sealed and secured to the shaft  927  of the hypodermic needle  902  to prevent leakage of the medication  913  from the collapsible canister  917 . 
     A proximal plate  931  disposed at a proximal end  932  of the collapsible canister  917  is slidingly fitted to a proximal portion  933  of the shaft  927  of the hypodermic needle  902  with a sliding seal  934 . The sliding seal  934  prevents leakage of the agent or medication  913  between the seal  934  and an outside surface of the shaft  927  of the hypodermic needle  902 . The sliding seal allows the proximal plate  931  of the collapsible canister  917  to slide axially along the needle  902  relative to the distal plate  925  of the collapsible canister  917 . A drug dose may be loaded into the main chamber  918  of the collapsible canister  917  during manufacture, and the entire assembly protected during shipping and storage by packaging and guide fins  935  surrounding the drive head slot  936  of the agent injection module  915 . 
     An injection cycle may begin when the agent injection module  915  is loaded into a ratchet advance mechanism (not shown), and registered at a drive position with a drive head  937  of the hypodermic needle  902  engaged in the drive coupler  185 . The position of the hypodermic needle  902  and collapsible canister  917  in this ready position is shown in  FIG. 99 . 
     Once the drive head  937  of the agent injection module  915  is loaded into the driver coupler  185 , the controllable driver can then be used to launch the injection member  916  including the hypodermic needle  902  and collapsible canister  917  towards and into the patient&#39;s tissue  903  at a high velocity to a pre-determined depth into the patient&#39;s skin or other organ. The velocity of the injection member  916  at the point of contact with the patient&#39;s skin  903  or other tissue can be up to about 10 meters per second for some embodiments, specifically, about 2 to about 5 m/s. In some embodiments, the velocity of the injection member  916  may be about 2 to about 10 m/s at the point of contact with the patient&#39;s skin  903 . As the collapsible canister  917  moves with the hypodermic needle  902 , the proximal plate  931  of the collapsible canister  917  passes between two latch springs  938  of module body  939  that snap in behind the proximal plate  931  when the collapsible canister  917  reaches the end of the penetration stroke, as shown in  FIG. 100 . 
     The controllable driver then reverses, applies force in the opposite retrograde direction and begins to slowly (relative to the velocity of the penetration stroke) retract the hypodermic needle  902 . The hypodermic needle  902  slides through the sliding seal  934  of the collapsible canister  917  while carrying the distal plate  925  of the collapsible canister with it in a proximal direction relative to the proximal plate  931  of the collapsible canister  917 . This relative motion between the distal plate  925  of the collapsible canister  917  and the proximal plate  931  of the collapsible canister  917  causes the volume of the main chamber  918  to decrease. The decreasing volume of the main chamber  918  forces the drug or other agent  913  disposed within the main chamber  918  of the collapsible canister  917  out of the main chamber  918  into the inlet port  922  in the shaft  927  of the hypodermic needle  902 . The inlet port  922  of the hypodermic needle  902  is disposed within an in fluid communication with the main chamber  918  of the collapsible canister  917  as shown in  FIG. 80 . The drug or agent then passes through the central lumen  923  of the hollow shaft  927  of the hypodermic needle  902  and is then dispensed from the output port  912  at the distal end  901  of the hypodermic needle  902  into the target tissue  903 . The rate of perfusion of the drug or other agent  913  may be determined by an inside diameter or transverse dimension of the collapsible canister  917 . The rate of perfusion may also be determined by the viscosity of the drug or agent  913  being delivered, the transverse dimension or diameter of the central lumen  923 , the input port  922 , or the output port  912  of the hypodermic needle  902 , as well as other parameters. 
     During the proximal retrograde retraction stroke of the hypodermic needle  902 , drug delivery continues until the main chamber  918  of the collapsible canister  917  is fully collapsed as shown in  FIG. 101 . At this point, the drive coupler  185  may continue to be retracted until the drive head  937  of the hypodermic needle  902  breaks free or the distal seal  941  between the distal plate  925  of the chamber and the hypodermic needle  902  fails, allowing the drive coupler  185  to return to a starting position. The distal tip  901  of the hypodermic needle  902  can be driven to a precise penetration depth within the tissue  903  of the patient using any of the methods or devices discussed above with regard to achieving a desired penetration depth using a controllable driver or any other suitable driver. 
     In another embodiment, the agent injection module  915  is loaded into a ratchet advance mechanism that includes an adjustable or movable distal stage or surface (not shown) that positions the agent injection  915  module relative to a skin contact point or surface  942 . In this way, an agent delivery module  915  having a penetration stroke of predetermined fixed length, such as shown in  FIGS. 99-101 , reaches a pre-settable penetration depth. The movable stage remains stationary during a drug delivery cycle. In a variation of this embodiment, the moveable stage motion may be coordinated with a withdrawal of the hypodermic needle  902  to further control the depth of drug delivery. 
     In another embodiment, the latch springs  938  shown in the agent injection module  915  of  FIGS. 99-101  may be molded with a number of ratchet teeth (not shown) that engage the proximal end  932  of the collapsible canister  917  as it passes by on the penetration stroke. If the predetermined depth of penetration is less than the full stroke, the intermediate teeth retain the proximal end  932  of the collapsible canister  917  during the withdrawal stroke in order to collapse the main chamber  918  of the collapsible canister  917  and dispense the drug or agent  913  as discussed above. 
     In yet another embodiment, drive fingers (not shown) are secured to an actuation mechanism (not shown) and replace the latch springs  938 . The actuation mechanism is driven electronically in conjunction with the controllable driver by a processor or controller, such as the processor  60  discussed above, to control the rate and amount of drug delivered anywhere in the actuation cycle. This embodiment allows the delivery of medication during the actuation cycle as well as the retraction cycle. 
     Inherent in the position and velocity control system of a controllable driver is the ability to precisely define the position in space of the hypodermic needle  902 , allowing finite placement of the hypodermic needle in the skin  903  for injection of drugs, vaccines or the like. Drug delivery can be discrete or continuous depending on the need. 
       FIGS. 102-106  illustrate an embodiment of a cartridge  945  that may be used for sampling that has both a lancet cartridge body  946  and an sampling cartridge body  947 . The sampling cartridge body  947  includes a plurality of sampling module portions  948  that are disposed radially from a longitudinal axis  949  of the sampling cartridge body  947 . The lancet cartridge body  946  includes a plurality of lancet module portions  950  that have a lancet channel  951  with a lancet  183  slidably disposed therein. The lancet module portions  950  are disposed radially from a longitudinal axis  952  of the lancet cartridge body  946 . 
     The sampling cartridge body  947  and lancet cartridge body  946  are disposed adjacent each other in an operative configuration such that each lancet module portion  950  can be readily aligned in a functional arrangement with each sampling module portion  948 . In the embodiment shown in  FIGS. 102-106 , the sampling cartridge body  947  is rotatable with respect to the lancet cartridge body  946  in order to align any lancet channel  951  and corresponding lancet  183  of the lancet cartridge body  946  with any of the lancet channels  953  of the sampling module portions  948  of the sampling cartridge body  947 . The operative configuration of the relative location and rotatable coupling of the sampling cartridge body  947  and lancet cartridge body  946  allow ready alignment of lancet channels  951  and  953  in order to achieve a functional arrangement of a particular lancet module portion  950  and sampling module portion  948 . For the embodiment shown, the relative motion used to align the particular lancet module portions  950  and sampling module portions  948  is confined to a single degree of freedom via relative rotation. 
     The ability of the cartridge  945  to align the various sampling module  948  portions and lancet module portions  950  allows the user to use a single lancet  183  of a particular lancet module portion  950  with multiple sampling module portions  948  of the sampling cartridge body  947 . In addition, multiple different lancets  183  of lancet module portions  950  could be used to obtain a sample in a single sampling module portion  948  of the sampling cartridge body  947  if a fresh unused lancet  183  is required or desired for each lancing action and previous lancing cycles have been unsuccessful in obtaining a usable sample. 
       FIG. 102  shows an exploded view in perspective of the cartridge  945 , which has a proximal end portion  954  and a distal end portion  955 . The lancet cartridge body  946  is disposed at the proximal end portion  954  of the cartridge  945  and has a plurality of lancet module portions  950 , such as the lancet module portion  950  shown in  FIG. 103 . Each lancet module portion  950  has a lancet channel  951  with a lancet  183  slidably disposed within the lancet channel  951 . The lancet channels  951  are substantially parallel to the longitudinal axis  952  of the lancet cartridge body  946 . The lancets  183  shown have a drive head  198 , shaft portion  201  and sharpened tip  196 . The drive head  198  of the lancets are configured to couple to a drive coupler (not shown), such as the drive coupler  185  discussed above. 
     The lancets  183  are free to slide in the respective lancet channels  951  and are nominally disposed with the sharpened tip  196  withdrawn into the lancet channel  951  to protect the tip  196  and allow relative rotational motion between the lancet cartridge body  946  and the sampling cartridge body  947  as shown by arrow  956  and arrow  957  in  FIG. 102 . The radial center of each lancet channel  951  is disposed a fixed, known radial distance from the longitudinal axis  952  of the lancet cartridge body  946  and a longitudinal axis  958  of the cartridge  945 . By disposing each lancet channel  951  a fixed known radial distance from the longitudinal axes  952  and  958  of the lancet cartridge body  946  and cartridge  945 , the lancet channels  951  can then be readily and repeatably aligned in a functional arrangement with lancet channels  953  of the sampling cartridge body  947 . The lancet cartridge body  946  rotates about a removable pivot shaft  959  which has a longitudinal axis  960  that is coaxial with the longitudinal axes  952  and  950  of the lancet cartridge body  946  and cartridge  945 . 
     The sampling cartridge body  947  is disposed at the distal end portion  955  of the cartridge and has a plurality of sampling module portions  948  disposed radially about the longitudinal axis  949  of the sampling cartridge body  947 . The longitudinal axis  949  of the sampling cartridge body  947  is coaxial with the longitudinal axes  952 ,  958  and  960  of the lancet cartridge body  946 , cartridge  945  and pivot shaft  959 . The sampling cartridge body  947  may also rotate about the pivot shaft  959 . In order to achieve precise relative motion between the lancet cartridge body  946  and the sampling cartridge body  947 , one or both of the cartridge bodies  946  and  947  must be rotatable about the pivot shaft  959 , however, it is not necessary for both to be rotatable about the pivot shaft  959 , that is, one of the cartridge bodies  946  and  947  may be secured, permanently or removably, to the pivot shaft  959 . 
     The sampling cartridge body  947  includes a base  961  and a cover sheet  962  that covers a proximal surface  963  of the base forming a fluid tight seal. Each sampling module portion  948  of the sampling cartridge body  947 , such as the sampling module portion  948  shown in  FIG. 104  (without the cover sheet for clarity of illustration), has a sample reservoir  964  and a lancet channel  953 . The sample reservoir  964  has a vent  965  at an outward radial end that allows the sample reservoir  964  to readily fill with a fluid sample. The sample reservoir  964  is in fluid communication with the respective lancet channel  953  which extends substantially parallel to the longitudinal axis  949  of the sampling cartridge body  947 . The lancet channel  953  is disposed at the inward radial end of the sample reservoir  964 . 
     The lancet channels  953  of the sample cartridge body  947  allow passage of the lancet  183  and also function as a sample flow channel  966  extending from an inlet port  967  of the lancet channel  953 , shown in  FIG. 106 , to the sample reservoir  964 . Note that a proximal surface  968  of the cover sheet  962  is spatially separated from a distal surface  969  of the lancet cartridge body  946  at the lancet channel site in order to prevent any fluid sample from being drawn by capillary action into the lancet channels  951  of the lancet cartridge body  946 . The spatial separation of the proximal surface  968  of the cover sheet  962  from the distal surface  969  of the lancet cartridge body  946  is achieved with a boss  970  between the two surfaces  968  and  969  that is formed into the distal surface  969  of the lancet cartridge body as shown in  FIG. 105 . 
     The sample reservoirs  964  of the sampling cartridge body  947  may include any of the sample detection sensors, testing sensors, sensor contacts or the like discussed above with regard to other sampling module embodiments. The cover sheet  962  may be formed of PMMA and have conductors, sensors or sensor contacts formed on a surface thereof. It may also be desirable to have the cover sheet  962  made from a transparent or translucent material in order to use optical sensing or testing methods for samples obtained in the sample reservoirs. In the embodiment shown, the outer radial location of at least a portion of the sample reservoirs  964  of the sampling cartridge body  967  is beyond an outer radial dimension of the lancet cartridge body  946 . Thus, an optical detector or sensor  971 , such as shown in  FIG. 105 , can detect or test a sample disposed within a sample reservoir  964  by transmitting an optical signal through the cover sheet  962  and receiving an optical signal from the sample. 
     The cartridge bodies  946  and  947  may have features, dimensions or materials that are the same as, or similar to, features, dimensions or materials of the sampling cartridges and lancet cartridges, or any components thereof, discussed above. The module portions  948  and  950  may also have features, dimensions or materials that are the same as, or similar to, features, dimensions or materials of the lancet or sampling modules, or any components thereof, discussed above. In addition, the cartridge  945  can be coupled to, or positioned adjacent any of the drivers discussed above, or any other suitable driver, in an operative configuration whereby the lancets of the lancet cartridge body can be selectively driven in a lancing cycle. Although the embodiment shown in  FIGS. 102-106  allows for alignment of various sampling module portions  948  and lancet module portions  950  with relative rotational movement, other embodiments that function similarly are also contemplated. For example, lancet module portions, sampling module portions or both, could be arranged in a two dimensional array with relative x-y motion being used to align the module portions in a functional arrangement. Such relative x-y motion could be accomplished with position sensors and servo motors in such an alternative embodiment order to achieve the alignment. 
     Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the appended claims.