Patent Publication Number: US-2018049684-A1

Title: Enhanced Lancing Device with Suction

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The invention generally relates to surgery and to collecting a liquid from the body. More specifically, the invention relates to improvements in housing and operating a lancet, which is a sharp edge or point for piercing the skin to draw blood. Further, the invention relates to an improved device for use in cutting, puncturing, or piercing the body or a specific portion thereof. Such piercing is by a lancet or similar instrument with a short, wide, double edged, pointed blade that cuts as the instrument is advanced longitudinally, or a blade that can repeatedly produce an incision of specific length, or an incision of specific length and of specific depth in body tissue. The invention further relates to a device employing a lancet blade that is actuated from a checked or inoperative position when released to an operative position by an energy storing resilient means. The invention is especially applicable to applying user-controlled variable suction or vacuum to skin area adjacent to and surrounding a pierced location. 
     Description of Prior Art 
     To monitor and treat various diseases and conditions such as diabetes, taking a blood sample is required of many people, often numerous times during a single day. Instruments known as lancet devices provide a quick means for producing a sample of blood for analysis. A basic lancet device is a housing with a longitudinally slidable holder for a puncturing element at a forward or distal end thereof. Different styles of puncturing elements can be used, including needles and blades. For convenient reference, the puncturing element will be generally referred to as a blade without limiting the scope of puncturing elements included therein. The puncturing element holder or blade holder can receive and carry a disposable puncturing element or lancet blade with the blade extending forward. As an aid to initial placement of the lancet device on the user&#39;s skin, a nose or spacer element at the forward or distal end of the housing is suitably long to space the housing, lancet blade holder, and lancet blade from the user&#39;s skin when the spacer is pressed against the skin prior to triggering. The lancet device can be cocked to place the lancet device in a ready condition for the blade to be released or triggered to spring forward from the spacer and pierce the user&#39;s skin. A basic lancet device contains an actuator to drive the lancet blade forward. For example, a mechanical cocking element can compress a spring that will drive the lancet holder forward when released. The cocking element also may employ a checking element to lock the lancet holder in a checked position, awaiting release. 
     When released, the blade moves forward and pierces the user&#39;s skin. The tip of the blade will extend forward from the distal end of the spacer. A trigger element associated with the housing can be actuated to release the lancet holder from checked position; whereupon the spring will cause the lancet holder to shoot forward, rapidly sliding the lancet blade forward and through the open end of the spacer to pierce the user&#39;s skin where the open forward end of the spacer is pressed against the skin. The spring or other driving actuator allows the blade to pierce the user&#39;s skin and then withdraw. For example, a spring actuator may allow the blade to continue forward by inertia, beyond a position of neutral spring forces, such that after puncturing the user&#39;s skin, the blade springs back from its maximum forward position. The maximum forward extension beyond a location of neutral forces represents the depth of skin penetration. Thus, lancet devices of this type are able to pierce the user&#39;s skin so rapidly, and with controlled depth, that there is little discomfort, producing a drop of blood for sampling. 
     Variations in the features of lancet devices provide differences in performance. A lancet device can be constructed to apply vacuum to the piercing site by incorporating a vacuum chamber in the housing, behind the lancet holder. In such a lancet device, a spring-loaded piston can be checked in a forward position. When triggered to be released, the piston shoots backwards, thereby creating a vacuum or low pressure volume in the vacuum chamber. At the same time, the lancet blade is advanced to pierce the user&#39;s skin similarly to the previous description. However, this device differs because the vacuum is applied through the space to the pierced skin area surrounding the lancet. The vacuum is maintained due to the seal established between the forward end of the spacer and the user&#39;s skin. The trigger defines a vent hole that is covered by the user&#39;s finger during triggering operation. By moving his finger from the vent hole, the user can open the vent and dissipate the vacuum before attempting to remove the lancet device from the user&#39;s skin. 
     Some users have found that the fixed vacuum of such a lancet device is stronger than they wish to experience. Also, users who might like the advantages of a vacuum feature may find that the cost of the vacuum feature is too high. The basic lancet devices, without any vacuum pump, tend to be far more economical. 
     It would be desirable to achieve the economy of a basic lancet device while providing access to a vacuum feature, as desired. Maintaining a low cost in a medical device is widely important and desired, especially among frequent users of such a device. 
     It would be desirable to allow the user or patient to vary the degree of vacuum according to his own needs. In many cases, the user and the patient are the same person, who then can judge when vacuum is sufficient. In other cases, such as with a parent who assists his child, the parent is the user. The parent and child can determine between them how much vacuum is desired or needed. 
     To achieve the foregoing and other objects and in accordance with the purpose of the present invention, as embodied and broadly described herein, the method and apparatus of this invention may comprise the following. 
     SUMMARY OF THE INVENTION 
     The accompanying drawings, which are incorporated in and form a part of the specification, illustrate preferred embodiments of the present invention, and together with the description, serve to explain the principles of the invention. In the drawings: 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG. 1  is an assembly view of a first embodiment of the lancing device with variable suction, with dashed lines suggesting an order of assembly. 
         FIG. 2  is a side elevational view of the lancing device with variable suction, showing the device in fully assembled configuration. 
         FIG. 3  (Prior Art) is a top plan view of a core lancet device. 
         FIG. 4  is a top plan view of a base section of an external housing, showing a vacuum pump in a cavity of thereof. 
         FIG. 5  is a view similar to  FIG. 4 , showing addition of a processor and battery to the cavity therein. 
         FIG. 6  is a view similar to  FIG. 5 , showing addition of a lancet device to the cavity therein. 
         FIG. 7  is a top plan view of an inverted cover section of an external housing. 
         FIG. 8  a top plan view of a closed external housing with a lancet device contained therein. 
         FIG. 9  is an isometric assembly view of an enhanced lancet device, with dashed lines suggesting an order of assembly. 
         FIG. 10  is an enlarged, isometric, detail view of the distal end of an enhanced lancet device, showing assembly of an external housing to a vacuum shell. 
         FIG. 11  is an enlarged isometric detail view of the distal end of an enhanced lancet device, showing a vacuum shell joined to an external housing of the enhanced lancet device. 
         FIG. 12  is an isometric view, taken from the right rear, of a vacuum shell. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A core lancet device is an elongated housing that carries at its front end a longitudinally oriented holder for a puncturing element. Typically, the puncturing element is disposable and is easily installed and removed from the holder. Various types of puncturing elements can be used with a core lancet device, including needles and blades. For convenience of reference, the puncturing element sometimes will be referred to as a lancet blade, without limiting the scope of puncturing elements included therein. A driving actuator, which will be sometimes referred to as a spring, is associated with the holder to interact as a driving member after being appropriately cocked and then released. A cocking element of the core lancet device can cock the holder or driving actuator to a checked position. A triggering element can release the holder or driving actuator from checked position. The driving actuator operates such that when the holder is released from checked position, the actuator provides a driving force that rapidly moves the holder forward. When a lancet blade is mounted in the holder, the blade springs forward with the holder. A depth control mechanism is associated with the holder to allow the blade to penetrate a user&#39;s skin to a certain depth and then to withdraw. As an example of a depth control mechanism where a blade is driven forward by a spring, the blade might continue forward by inertia, going beyond a neutral position of the spring, and then spring back to a neutral position. The excess advancement due to inertia can be how the blade pierces the user&#39;s skin. The springing back to neutral position is how the blade can withdraw from the user&#39;s skin. Thus, the piercing is rapid and depth is limited, with the entire forward piercing and rearward withdrawal taking place so quickly that the eye may have trouble seeing it. 
     Typically a removable, hollow tubular spacer is attached as a front end of the core lancet housing, with the path of the blade aligned to pass through the centerline of the tubular shape. The length of the spacer is such that the blade does not extend out of the open forward end of the spacer, both when the holder is in neutral position and when the holder is checked position. However, the spacer is short enough that the blade will extend out of the open forward end of the spacer when the blade is released from cocked condition and springs forward beyond neutral location. The tubular spacer enables the user to press the core lancet device against his skin to pre-position the lancet device without contacting the blade. Some lancet devices include a depth control that alters the maximum extension of the blade beyond the spacer. The length of the spacer can accommodate adjustment of this type while protecting the user from premature contact with the blade. 
     Even after the user&#39;s skin has been pierced, it can be difficult to bring the drop of blood to the skin surface. Sometimes the user has to squeeze and rub the pierced skin area to bring out the blood sample. The present invention provides an enhanced lancet device that improves this situation by adding suction to the function of a core lancet device that was constructed without built-in provision for suction. An aspect of the invention is the discovery that a vacuum function can be added to a core lancet device to produce an enhanced lancet device, where the core lancet device was not equipped with its own vacuum function independent of an external housing. The invention adds a coordinated source of vacuum, suction, or low pressure air that is applied to a core lancet device over a selected span of time. Suction might be applied immediately prior to the skin piercing event in order to build up suction strength. Suction might be applied during the piercing event, itself, to preserve previously built up suction and to extract blood. Suction might be applied immediately after the piercing event to extract the sample of blood. 
     This invention is primarily directed to a core lancet device that is nested in an external vacuum housing. The term, “core,” refers to a lancet device or housing that is not especially configured to generate vacuum. Such a core lancet device is characterized by an absence of an internal vacuum chamber. A functional fit between parts can allow an external chamber to surround the core lancet with vacuum, other than at a forward nose near the holder for the lancet blade. The external vacuum establishes air seepage through the core lancet device from the forward nose, creating suction in proximity to a forward puncturing device or blade. The external vacuum chamber houses the core lancet except at the forward nose, which serves as a suction inlet point. Thus, in an enhanced lancet device, an external vacuum housing operates through a core lancet housing to draw suction in proximity of the lancet blade. When a spacer is attached to the forward nose, the suction inlet point is advanced to the front end of the spacer, which applies the suction to the user&#39;s skin where the lancet blade will pierce the skin. Thus, the open front of the spacer is an extension of the forward suction point. The internal low pressure air from the external housing and internal lancet housing draws in the higher pressure atmospheric air at the front nose of the lancet housing and around the lancet blade holder, creating external suction that is applied to the user&#39;s skin through the spacer. 
     In greater detail, the invention is an outer vacuum housing that contains a core lancet device or core lancet housing. The outer vacuum housing is substantially pressure sealed, other than through the core lancet housing. The core lancet housing serves as an inner housing contained within the outer vacuum housing so that the inner housing is substantially surrounded by low pressure or vacuum, other than at the front where the blade holder and lancet blade are located. The combined inner and outer housings provide variable vacuum or suction and, in use, apply it through a tubular spacer to a user&#39;s skin in the area that the lancet blade will pierce. 
     The front of the inner core lancet housing and the front of the external vacuum housing meet at a forward junction. The inner and outer housings can be fastened together at the junction. A suitable junction area of the core lancet housing is an outward facing cylindrical forward end that encircles the lancet holder. A suitable junction area of the outer housing is an inward facing cylindrical forward end that closely fits around the junction area of the core lancet device. The two junction areas are placed at the same end of the combined inner and outer housings and are aligned with the pathway for the lancet blade. 
     The two junction areas have complementary shapes to establish the junction at a perimeter around the position of the lancet blade holder so that the lancet blade can move forward to puncturing position without interference from the junction. The core lancet provides the inner side of the junction, while the external vacuum housing provides the outer side of the junction. The junction minimizes or eliminates vacuum leakage between the two mating structures. 
     A tubular spacer or shell is formed or attached to the front end of the enhanced lancet device, at the junction between the inner core lancet housing and the external vacuum housing. This junction encircles a suction point. The spacer or shell provides a lateral wall around the path of the lancet blade to bring suction forward, as needed, to apply suction to the user&#39;s skin in front of the cocked lancet blade. The spacer or shell is pressed against the user&#39;s skin to establish a known spacing to the cocked lancet blade. Then, when the trigger element releases the holder and blade, the blade advances on its path by a known distance that is sufficient for the blade to penetrate the user&#39;s skin. However, the known distance of blade travel is limited, so that penetration is sufficient for blood sampling but not needlessly deep into the user&#39;s skin. The spacer or shell provides both an application of suction to the penetration site and a limitation of how deep the blade can penetrate beyond the forward end of the spacer or shell. 
     According to the invention, a core lancet housing can serve as an inner housing that is nested within the outer or primary housing, with the exception that the blade holder and lancet blade are aligned with a passage to the outside. The outer housing serves as a vacuum chamber and cooperates with the inner core lancet housing to supply suction into the outside passage. The suction or vacuum is transmitted through the outside passage, which may laterally confine the suction through a tube or shell to reach a forward position at the user&#39;s skin. The tube or shell become sealed to apply suction against the user&#39;s skin when pressed against the user&#39;s skin, and as a result, the suction or vacuum then is applied to the user&#39;s skin at the location where the lancet blade will pierce it. The applied suction enhances extraction of a drop of blood for sampling. After use, typically the tubular spacer or shell is removed from the enhanced lancet device to gain access to the blade holder and the lancet blade is replaced. The spacer is reattached to prepare the enhanced lancet device for a next use. Several embodiments demonstrate the scope of this invention. 
     According to a first embodiment, the invention can be adapted for use with a core lancet housing of known configuration but lacking a vacuum feature. In such a version, an otherwise complete core lancet housing is nested inside a cavity within an external housing, which then is sealed against loss of vacuum other than through a portion of the lancet housing with outside access, such as within the junction. The sealed cavity provides a basis for applying suction or vacuum around substantially the entire lancet device, other than the junction. Reference to a sealed external housing or sealed cavity also allows for air access to the open tip of the spacer. Otherwise, the enhanced lancet device is sealed when pressed against the user&#39;s skin. The reference to a sealed external housing or sealed cavity also allows for discharge of air through an exit port from a source of suction to establish a zone of lower pressure in the cavity. 
     In order to provide vacuum to an internal nested lancet housing, the external housing is configured with a combination of vacuum resistant walls and access areas. The pre-existing controls of the core lancet housing are operated by limited deformation of the access areas. Access area covers and shrouds provide such desired deformation to allow operation of controls on the lancet housing. The access area covers sufficiently resist deformation under vacuum that a vacuum can be applied to a lancing location on the user&#39;s skin. 
     According to an alternate embodiment, the invention is adapted to a sealed primary housing that provides the functions and equipment of a lancet device. These are a sliding lancet carrier or holder, a resilient member such as a spring loaded against the sliding lancet holder, a cocking element for withdrawing the sliding lancet holder to withdrawn position, a check element for locking the sliding holder in withdrawn position, and a trigger element for releasing the lancet holder from withdrawn position to slide forward through a front opening, lancing the user&#39;s skin at the front opening. The invention is adapted to the primary housing by providing an access port and an external suction tube mounted to the port, enabling the user to draw a variable degree of vacuum within the sealed primary housing. 
     With reference to  FIG. 1 , an internal core lancet device is combined with an external housing. The internal core lancet device is formed of an elongated internal housing  10  that provides a longitudinally slidable lancet holder  12  that carries a disposable lancet blade  14 . A cocking element  16  places the lancet holder in ready position to spring forward within housing  10  to bring the lancet blade forward. A check element inside housing  10  engages to hold the cocked lancet holder in ready position. A trigger button  18  is pressed to release the lancet holder from the check element, resulting in the lancet holder&#39;s shooting forward with lancet blade  14  to pierce the user&#39;s skin. A tubular spacer  20  fits over the forward end of housing  10 . The forward end  22  of spacer  20  is open to allow the lancet blade  14  to extend out of the spacer to pierce the user&#39;s skin. 
     An external housing  24  is sized to receive internal housing  10 . According to this specific embodiment, the cocking element  16  protrudes above a proximal or rearward open end  26  of housing  24 . A flexible cap  28  fits onto rearward end  26  of external housing  24  and over cocking element  16 . A retention band  30  secures the cap  28  around housing end  26  and secures a seal between the housing  24  and cap  28 . The cap can be attached to housing  24  by any of various means, including pressure, adhesive, threads, or twist-lock (bayonet), to name several examples. Flexibility of the cap allows the user to pull cocking element  16  rearward to cock lancet holder  12  to checked position. If necessary, cap  28  can be formed of stretchable material to accommodate sufficient rearward movement of cocking element  16 . 
     Housing  24  receives trigger button  18  behind window  32 . The window is formed or covered by a panel that is flexible enough to allow selective operation of the button. The material of window  32  may be a soft plastic that is applied to the housing  24  to seal the window. As examples, the window panel can be set into the window opening, bonded around the window opening, or overlaid on the window opening, which can include the application of a ring of plastic that fits snugly around the housing  24 . Thus, the controls on the internal housing  10  are operable behind elastic, flexible, or otherwise accessible covers while the internal housing  10  is installed within the external housing  24 . 
     At the forward, distal end  34  of housing  24 , the spacer  20  is inserted into housing end  34 . The spacer typically is a component of the internal core lancing device and fits snugly onto the distal end of internal housing  10 . A seal  36  is applied to spacer  20  in a position to also seal with housing  24  at lower end  34 . 
     A port  38  is in communication with the inside volume of housing  24 . The port is sized to engage with an end  40  of a suction tube  42 . The opposite end  44  of the suction tube is suitable for engagement with a source of suction. The invention contemplates that the user will apply suction by mouth, so that the degree of suction is instantaneously variable at the user&#39;s discretion. 
     According to  FIG. 2 , the internal core lancet housing  10  nests within the assembled enhanced lancet housing  46  as a part thereof. In use, suction is applied through tube  42  to create a vacuum within housing  24 . In use, the open end  22  of tubular spacer  20  is sealed against the user&#39;s skin. Thus, in use, the enhanced lancet device  46  maintains vacuum according to the user&#39;s control through tube  42 . When the user wishes to release vacuum, he releases his suction on tube  42  and the enhanced lancet device  46  returns to ambient internal air pressure. 
       FIGS. 1 and 2  also suggest a configuration for a vacuum lancet device employing a suction hose  42 , without the need for an internal, nested lancet device. Sliding lancet holder, cocking device, and trigger device can be built into housing  24 , which is served by variable vacuum through tube  42  and port  38 . 
     Several different core lancet housings are commercially available.  FIGS. 3-8  show the concept of an external vacuum housing that can be applied to different commercially available core lancet housings  50 . Reference to a core lancet housing  50  refers to a core lancet device without necessarily including a front spacer  20  or the like that was a component of the core lancet device. A spacer or vacuum shell is employed in embodiments including the external vacuum housing, but this spacer may differ from the spacer that is part of the core lancet device. In particular, the original spacer  20  may have attached directly to the nose of a core lancer device, while a spacer used with an enhanced lancet device may differ by attaching directly to a nose of the external vacuum housing. 
     The internal housing  50  of  FIG. 3  provides a longitudinally slidable lancet holder  52  at the front end thereof for receiving and carrying a disposable lancet blade  14 . Conventionally, a biasing element  54  cocks or otherwise readies the lancet holder  52  for forward movement to a puncturing position. The biasing element  54  places the lancet holder in pre-actuated condition. The biasing element might include a spring or system of springs to spring-load the lancet holder to slide forward and puncture the user&#39;s skin with the tip of lancet blade  14 . While springs are a suitable driving force for a biasing element, other biasing means might be used. For example, magnets and resilient bands are other suitable choices. In one embodiment, a cocking slider  54  operates in a lateral slider slot  56  to slide rearward to a checked position, placing the lancet holder  52  in pre-actuated condition to spring forward when released. Typically a check element inside the housing  50  engages to hold the lancet holder  52  in cocked, pre-actuated position. A releasing means such as trigger button  58  is pressed to release the check element, placing the lancet holder in actuated, puncturing condition where the lancet holder  52  springs forward with the lancet blade  14  to puncture the user&#39;s skin. A cylindrical nose  60  is located at the forward end of the lancet housing  50  and laterally encircles the lancet holder  52  when in pre-actuated position. The cylindrical nose  60  is a suitable structure for attaching an external housing  62  to the front of the lancet housing  50 . 
     An external housing  62 ,  FIG. 9 , has an elongated, generally longitudinal shape and is sized to receive a core lancet housing  50 , thus forming an enhanced lancet housing  63 . The external housing opens or separates in a suitable way to receive the housing  50  and to be reassembled with the housing  50  nested within it, with the front of nose  60  open to external ambient air pressure. The housing  62  can be structured as at least two mating parts, such as a base and a cover. For example, housing  62  is composed of a base  64 , best shown in  FIGS. 4, 5 , and  6 , and a cover  66 , best shown in  FIG. 7 . The base portion  64  of the external lancet housing  62  is formed with an internal cavity  68  that receives core lancet housing  50 . The cavity  68  is illustrated as being located chiefly in the base portion  64  of housing  62 , although other locations or proportions can be equally acceptable. The cavity  68  also is configured to receive supporting devices. The specific locations of the supporting devices as shown in the drawings are merely suggestive and can be altered as required or preferred in a specific configuration. 
     As shown in  FIG. 4 , one such supporting device is a means for drawing vacuum within external housing  62 . The suction tube  42  allows the user to draw vacuum by suction applied to the outside end  44  of the tube. An automatic means for drawing vacuum is a micro vacuum pump formed of an electric motor  70  operating a connected pump  72 . The vacuum pump draws air from within the cavity  68  and discharges the air through an exit port  74  formed in a wall of the external housing  62 . When the cavity  68  is sealed by application of a cover and a junction with the core lancet device  50 , the operation of the vacuum pump produces low air pressure within the cavity  68 . 
     In addition to the vacuum pump, the housing base  64  carries a processor chip  76  that enables blood sample data to be analyzed. The chip  76  is connected to reading wires  78  that sense the content of a blood sample produced by the lancet blade  14 . The chip has communication ability to manage the blood data, to convey the reading via wireless means such as cellular, wi-fi, or Internet communication to a doctor, laboratory, recording device, or other chosen recipient. A battery  80  provides power to operate the chip  76  and vacuum pump  70 ,  72 . A manual on/off switch  82  is exposed in an external wall of the housing base  64  to enable the user to selectively operate the supporting devices in the housing  62 . 
     The cavity  68  also is configured to receive the core internal lancet housing  50 . The internal lancet housing  50  fits snugly within the cavity  68  with cylindrical nose  60  supported within a close fitting outer cylindrical ring  84  at the forward end of the housing  62 . Outer ring  84  provides a sufficient seal with nose  60  so that lower pressure or vacuum can be formed inside housing  62 . The ring  84  can be a part of housing  62 , or it can be a separate ring that is attached to housing  62 , such as by threads. Ring  84  also might be only a partial ring that is closed by a supplemental segment of the cover  66 , as described below. 
     As best shown in  FIG. 7 , cover  66  fits over and closes the cavity  68  and is contoured as necessary to accommodate the intended content of the cavity  68 . For example, the cover  66  might accommodate the processor chip  76  by providing a cavity portion  86  positioned over the intended location of the chip. Cover  66  might accommodate the core lancet housing  50 , battery  80  and vacuum pump  70 ,  72  by providing a suitably contoured cavity portion  88  positioned over the intended locations of the housing  50 , battery  80  and the vacuum pump  70 ,  72 . The cover  66  also provides a slot  88  that overlies slot  56  in the lancet housing  50  and enables the controls on the lancet housing to be operated while the housing  62  remains sealed. Slot  88  may be sealed by a flexible sheet of rubber, plastic, or other suitable material  90  that enables the controls on core lancet housing  50  to be manipulated while the cover  66  remains on the base  64 . Further, the cover  66  may include a cylinder segment  92 , if required, to complete the outer cylindrical ring  84 . 
     When cover  66  is applied to base  64 , the housing  62  is sealed against passage of air other than within the outer cylindrical ring  84  and preferably at cylindrical nose  60 . When cylindrical nose  60  is contained and sealed in the outer cylindrical ring  84 , suction can be drawn through nose  60  by seepage, as present. In this way, the ring  84  serves as a perimeter of a suction port. For example, cavity  68  will be at reduced air pressure due to the operation of pump  70 ,  72 . One possible point of entry for air is at nose  60 , around the edges of the lancet blade holder  52 , which is within cylindrical ring  84 . Any other likely point of entry for air, such as at the junction of nose  60  and ring  84 , is likewise within the perimeter established by ring  84 . These possible points of seepage are desirably located within suction port  84  to supply suction in proximity to the lancet blade  14 . 
     The use of a core lancet housing  50  contributes to the successful availability of vacuum at the lancet blade  14 . A core lancet housing is not especially sealed to contain its own vacuum. Instead, the core lancet housing becomes a transmitter of suction from the external housing  62  to the forward end of the internal lancet housing  50 , such as to nose  60  on the lancet housing  50 . Suction at nose  60  is in surrounding proximity to the lancet blade and can be further confined and directed by a spacer or shell  94  attached to ring  84 . 
     The external housing  62  serves as the primary vacuum chamber and relies on limited transmission of higher pressure air only within the suction port surrounded by ring  84 . This suction port is partially filled by the nose  60  of core lancet housing  50 , leaving seepage through the core lancet housing  50  into the external housing  62  as the transmittal path for suction through the suction port within ring  84 . 
     It would be desirable to further confine, contain, and guide this suction to apply it to a user&#39;s skin when the lancet blade has punctured the user&#39;s skin for the purpose of extracting a sample of blood. Suitably applied suction can aid in producing the sample of blood from the puncture. In order to apply suction to a user&#39;s skin, a vacuum shell  94  is attached around and in front of the outer cylindrical ring  84  of the external housing  62 . As shown in  FIGS. 9-12 , the vacuum shell  94  provides a smooth front contact edge  96  that can be pressed against the user&#39;s skin with sealing pressure, allowing vacuum to be applied within the perimeter established by edge  96 . The back end of the vacuum shell  94  is a cylindrical ring  98  that fits over cylindrical ring  84  at the front of the external housing  62 . Thus, whatever suction is available by seepage through cylindrical ring  84  is applied to the user&#39;s skin at the approximate area where the lancet blade  14  will be inserted. 
     In the assembled enhanced lancet device  63  of  FIG. 9 , the lancet blade  14  is located approximately on a common centerline of the three cylindrical rings consisting of the lancet housing nose  60 , the outer cylindrical ring  84 , and the shell cylinder  98 . This common centerline of the three cylindrical rings is indicated by the dashed line  100  in  FIGS. 9 and 10 , which also is aligned with the center axis of the lancet blade  14 . The known position of the common centerline  100  and, hence, the path of the lancet blade  14  allows the use of a sample collection strip  102  at a predetermined position in front of the cocked lancet blade  14 . The sample collection strip  102  can be prepositioned in alignment with the path of the lancet blade  14  so that the lancet blade  14  encounters the sample collection strip  102  in the same thrust in which the lancet blade  14  pierces the user&#39;s skin. In this location, the sample collection strip  102  overlies the precise location of the sampling pierce along the path of dashed line  100  so that the resulting sample of extracted blood is immediately captured on the sample collection strip  102 . 
     In greater detail, the sample collection strip  102  is positioned at the front of the vacuum shell  94  so that the user&#39;s skin surface supports the sample collection strip  102  for the lancet blade  14  to engage the sample collection strip  102  in the same thrust as the lancet blade pierces the user&#39;s skin. The vacuum shell  94  is configured to maintain the sample collection strip in the desired position. For example, the sample collection strip  102  can be shaped as a disk, and the vacuum shell  94  might define a circular shell portion  104  of similar outlined size and shape as the disk. To better retain the sample collection strip  102  in the desired location, a mount or fastener can be used. For example as shown in  FIG. 9 , the vacuum shell  94  may include a mounting pin  106  that engages the sample collection strip  102  in a central mounting aperture  108 . In a disk shaped sample collection strip  102 , the location of the mounting aperture  108  may be at the center of the disk shape so that the sample collection strip  102  can be rotated on pin  106  while remaining within the boundaries of the shell portion  104 . 
     Pin  106  is offset from the centerline of shell cylinder  98 , although the offset preferably is smaller than or equal to the radius of the disk-shaped sampling strip  102 . The center axis of the mounting pin  106  is represented by dashed line  110  in  FIG. 9 . The offset between dashed lines  100  and  110  is readily known. Thus, the sampling strip  102  is arranged such that the lancet  14  can pierce or otherwise engage the disk  102  between its center  108  and its outer edge or perimeter, depending upon the magnitude of the offset. An offset of one-half the radius or greater is desirable because it approaches the wider area of the sampling strip  102 , near its perimeter. This positioning provides a substantial surface area of the sampling strip  102  to receive the blood sample and maintain the sample on the sampling strip. 
     According to the sampling method where the lancet blade passes through collection strip  102  and then pierces the user&#39;s skin, the lancet blade might sever a fleck of the collection strip  102  during advancement. It would be desirable to prevent forming such flecks and to avoid the accidental transfer of a fleck into the user&#39;s skin with the tip of the lancet blade. The chance of this sort of transfer is minimized by pre-forming a lancet passage  112  through the sampling strip  102  in the lancet blade&#39;s line of travel. A plurality of lancet blade passages  112  can be formed at equal spacing from central aperture  108 , thus lying in a ring around aperture  108 . The plurality of lancet blade passages  112  also may be separated by equal angles. By rotating the collection strip around aperture  108 , any one of the passages  112  can be positioned in line with the lancet blade, in what can be termed the active area of the collection strip. Likewise, the passage  112  aligned with the blade can be called the active passage. Other passages  112 , currently not in the active area, can be used to index the position of the collection strip so that the active passage  112  maintains alignment with the lancet blade. In  FIG. 10 , it is evident that dashed line  100  not only originates in alignment to the lancet blade  14 , but the dashed line  100  also aligns with a pre-formed, active passage  112  in the sampling strip  102 .  FIG. 11  illustrates the resulting engagement between the lancet blade  14  and the pre-formed, active passage  112  in sampling strip  102 . 
     The desired alignment of the lancet blade  14  with the active passage  112  is made possible by knowing the offset represented by the separation of dashed lines  100  and  110 , as well as by locating the sampling strip in a known rotational position to place an active passage  112  in alignment with the path of the lancet blade. The rotational position of an active passage  112  is readily controlled by an indexing device acting between the vacuum shell  94  and the sampling strip  102 . For example, in  FIGS. 9 and 10 , an indexing pin  114  is positioned to engage one of the passages  112 , other than the active passage  112  that is aligned with the lancet blade. 
     The illustrated sampling strip  102  is configured to have a plurality of sampling areas  116  equally spaced around central mounting aperture  108 . For example, in the drawings a single sampling strip is divided into eight sampling sectors  116 . Each sampling area  116  is configured with a pre-formed passage  112  in the proper location to align with the lancet blade when the sampling strip  102  is suitably rotated and indexed to place a selected sampling area  116  in the active position. The single sampling strip  102  then can be used as many times as there are sectors  116  by rotating the sampling strip on the mounting pin  106 , placing one sector after another into the active indexed position that is aligned with the lancet blade. 
     The reading wires  78  can be positioned to contact the active sampling area  116 . In  FIGS. 10 and 11 , the reading wires  78  extend forward from the junction of ring  84  and nose  60 , such that the reading wires are in a suitable position to engage the active area  116  and obtain readings of the blood sample, when present. 
     The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be regarded as falling within the scope of the invention as defined by the claims that follow.