Abstract:
The present invention relates generally to systems, apparatuses, and methods for obtaining a fluid sample from a patient. In particular, the present invention relates to a various types of fluid access interfaces for enabling contact between a patient blood sample and blood parameter sensors for the measurement of physiological parameters and blood constituents.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a divisional of U.S. application Ser. No. 11/419,784, filed on May 23, 2006, which is hereby incorporated by reference in its entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates generally to systems, apparatuses, and methods for obtaining a fluid sample from a patient. In particular, the present invention relates to a fluid access interface for accessing a blood sample present in tubing, such as, for example, a vascular access line connected to a patient. In addition, the present invention relates to a fluid access interface for enabling contact between a patient blood sample and sensors, such as blood parameter testing strips, for the measurement of physiological parameters and blood constituents. More specifically, the fluid access interfaces of the present invention may be used in conjunction with a system for automated blood glucose measurement and testing. 
       BACKGROUND OF THE INVENTION 
       [0003]    Patient blood chemistry and monitoring of patient blood chemistry are important diagnostic tools in patient care. For example, the measurement of blood analytes and parameters often give much needed patient information in the proper amounts and time periods over which to administer a drug. Blood analytes and parameters tend to change frequently, however, especially in the case of a patient under continual treatment, thus making the measurement process tedious, frequent, and difficult to manage. 
         [0004]    Blood glucose levels must be maintained within a narrow range (about 3.5-6.5 mM). Glucose levels lower than this range (hypoglycemia) may lead to mental confusion, coma, or death. High glucose levels (hyperglycemia) have been linked to severe complications, including kidney damage, neural damage, and blindness. 
         [0005]    Conventional glucose measurement techniques require lancing a convenient part of the body (normally a fingertip) with a lancet, milking the finger to produce a drop of blood, and depositing the drop of blood on a measurement device (such as an glucose testing strip). This lancing method is both painful and inconvenient for the patient. The pain and inconvenience has additional and more serious implications of noncompliance. Patients generally avoid maintaining the recommended regimen of blood glucose measurement and thereby run the risk of improper glucose levels and consequent harmful effects. 
         [0006]    The conventional Point-of-Care (POC) techniques for diagnostic blood testing are routinely performed manually at the bedside using a small sample of blood. 
         [0007]    SureStep® Technology, developed by Lifescan, is one example of a conventional Point-of-Care diagnostic system. The SureStep® Technology, in its basic form allows for simple, single button testing, quick results, blood sample confirmation, and test memory. In operation, the SureStep® Point-of-Care system employs three critical steps for performance. In a first step, the blood sample is applied to the test strip. The blood sample is deposited on an absorbent pad, which is touchable and promotes quick, convenient, and safe sample application. In addition, blood is retained and not transferred to other surfaces. The sample then flows one way through the porous pad to the reagent membrane, where the reaction occurs. The reagent membrane is employed to filter out red blood cells while allowing plasma to move through. In a second step, the glucose reacts with the reagents in the test strip. Glucose in the sample is oxidized by glucose oxidase (GO) in the presence of atmospheric oxygen, forming hydrogen peroxide (H 2 O 2 ). H 2 O 2  reacts with indicator dyes using horseradish peroxidase (HRP), forming a chromophore or light-absorbing dye. The intensity of color formed at the end of the reaction is proportional to the glucose present in the sample. 
         [0008]    In a third step, the blood glucose concentration is measured with SureStep® meters. Reflectance photometry quantifies the intensity of the colored product generated by the enzymatic reaction. The colored product absorbs the light—the more glucose in a sample (and thus the more colored product on a test strip), the less reflected light. A detector captures the reflected light, converts it into an electronic signal, and translates it into a corresponding glucose concentration. The system is calibrated to give plasma glucose values. 
         [0009]    Prior art devices have conventionally focused upon manually obtaining blood samples from in-dwelling catheters. Such catheters may be placed in venous or arterial vessels, centrally or peripherally. For example, Edwards LifeSciences&#39; VAMP Plus Closed Blood Sampling System provides a safe method for the withdrawal of blood samples from pressure monitoring lines. The blood sampling system is designed for use with disposable and reusable pressure transducers and for connection to central line catheters, venous, and arterial catheters where the system can be flushed clear after sampling. The blood sampling system mentioned above, however, is for use only on patients requiring periodic manual withdrawal of blood samples from arterial and central line catheters that are attached to pressure monitoring lines. 
         [0010]    The VAMP Plus design provides a needleless blood sampling system, employing a blunt cannula for drawing of blood samples. In addition, a self-sealing port reduces the risk of infection. The VAMP Plus system employs a large reservoir with two sample sites. Two methods may be used to draw a blood sample in the VAMP Plus Blood Sampling System. The first method, the syringe method for drawing blood samples, first requires that the VAMP Plus is prepared for drawing a blood sample by drawing a clearing volume (preferred methods provided in the literature). To draw a blood sample, it is recommended that a preassembled packaged VAMP NeedleLess cannula and syringe is used. Then, the syringe plunger should be depressed to the bottom of the syringe barrel. The cannula is then pushed into the sampling site. The blood sample is then drawn into the syringe. A Blood Transfer Unit is then employed to transfer the blood sample from the syringe to the vacuum tubes. 
         [0011]    The second method allows for a direct draw of blood samples. Again, the VAMP Plus is first prepared for drawing a blood sample by drawing a clearing volume. To draw a blood sample, the VAMP Direct Draw Unit is employed. The cannula of the Direct Draw Unit is pushed into the sampling site. The selected vacuum tube is inserted into the open end of the Direct Draw Unit and the vacuum tube is filled to the desired volume. 
         [0012]    The abovementioned prior art systems, however, have numerous disadvantages. In particular, manually obtaining blood samples from in-dwelling catheters tends to be cumbersome for the patient and healthcare providers. 
         [0013]    In the light of above described disadvantages, there is a need for improved methods and systems that can provide comprehensive blood parameter testing. 
         [0014]    What is also needed is a programmable, automated system and method for obtaining blood samples for testing certain blood parameters and data management of measurement results, thus avoiding human recording errors and providing for central data analysis and monitoring. 
         [0015]    In addition, what is needed are systems, methods, and apparatuses for enabling fluid sampling in automated blood parameter testing systems. 
         [0016]    More specifically, what is needed are fluid sampling interface apparatuses and methods for using such apparatuses with automated blood parameter testing systems. 
       SUMMARY OF THE INVENTION 
       [0017]    The present invention is directed toward a plurality of embodiments capable of accessing a blood sample, present in a vascular access line connected to a patient, or any other form of tubing. In one embodiment, the present invention is a device for accessing a blood sample from a patient and measuring blood constituents, comprising a single use flexible transfer tube having a shape, wherein the single use transfer tube is used to provide a direct fluid flow path to a test substrate and wherein an alteration in the shape of the tube causes the tube to move from an open state to a closed state. In an open state, the tube provides a blood sample to a proximally located testing site, such as a testing strip or sensor. 
         [0018]    In another embodiment, the present invention is a device for accessing a blood sample from a patient and bringing the blood samples to a transfer tube in combination with a test strip holder. The test strip holder positions a test strip for fluid dispensing and mechanical handling. The distal end may be an end-access capillary test strip for glucose measurement. 
         [0019]    The transfer tube may be used to access fluid from a main fluid line to determine the concentration of at least one analyte, wherein the main fluid tube further comprises a tube originating from a vascular access point, a pump fixedly attached to the tube, a valve fixedly attached to the tube and located above the pump mechanism, at least one measurement element, a needle-less port, for accessing the main fluid tube; and an electronic meter. 
         [0020]    In another embodiment, the present invention is directed toward a device for accessing a blood sample, present in a vascular access line connected to a patient or any other form of tubing and measuring blood constituents, comprising a transfer tube with a closed end used to remove fluid from a needle-less access port and to a test substrate, wherein the closed end of the transfer tube is a bulb which can be expanded and contracted to access a fluid sample. 
         [0021]    Optionally, the transfer tube comprises a micro-syringe, wherein the micro-syringe comprises a plunger to remove and deposit a fluid sample onto a test substrate. The closed-end transfer tube is used to access fluid from a main fluid line to determine the concentration of at least one analyte, wherein the main fluid line further comprises a tube originating from a vascular access point, a pump fixedly attached to the tube, a valve fixedly attached to the tube and located above the pump mechanism, at least one measurement element, a needle-less port for accessing the main fluid line, and an electronic meter. 
         [0022]    In another embodiment, the present invention is directed toward a device for accessing a blood sample, present in a vascular access line connected to a patient or any other form of tubing and measuring blood constituents, comprising a piston pump, wherein the piston pump is connected to a transfer tube and said piston pump is used to remove a fluid sample and deliver the fluid sample to a test substrate. The piston pump is used to access fluid from a main fluid line to determine the concentration of at least one analyte, wherein the fluid line is further used with a tube originating from a vascular access point, a pump fixedly attached to the tube, a valve fixedly attached to the tube and located above the pump mechanism, at least one measurement element, a needle-less port, for accessing the main fluid line, and an electronic meter. 
         [0023]    In another embodiment, the present invention is directed toward a device for accessing a blood sample, present in a vascular access line connected to a patient or any other form of tubing and measuring blood constituents, comprising a shuttle, wherein said shuttle is a single-use device used to facilitate drawing a sanitary and uncontaminated fluid sample through a sampling port without passing back through the sampling port. 
         [0024]    Optionally, the shuttle device penetrates through a dual-sided needle-less port. The shuttle device is used to access fluid from a main fluid line to determine the concentration of at least one analyte, wherein the fluid line is further used with a tube originating from a vascular access point, a pump fixedly attached to the tube, a valve fixedly attached to the tube and located above the pump mechanism, at least one measurement element, a dual-sided needle-less port, for accessing the main fluid line, and an electronic meter. 
         [0025]    In another embodiment, the present invention is directed toward a device for accessing a blood sample, present in a vascular access line connected to a patient or any other form of tubing and measuring blood constituents, comprising an air jet fluid access port, which further comprises a valve and a low volume air pump. The air jet fluid access port is used to access fluid from a fluid line to determine the concentration of at least one analyte, wherein the fluid line is used with a tube originating from a vascular access point, a pump fixedly attached to the tube, a valve fixedly attached to the tube and located above the pump mechanism, at least one measurement element, a needle-less port, for facilitating access to the main fluid line, and an electronic meter. 
         [0026]    In another embodiment, the present invention is directed toward a device for accessing a blood sample, present in a vascular access line connected to a patient or any other form of tubing and measuring blood constituents, comprising a distribution valve wherein said distribution valve is used to redirect a main flow of fluid to a side path. Optionally, the distribution valve is a by-pass valve. Optionally, the distribution valve has zero dead volume. Optionally, the distribution valve has a micro filter positioned at one or more ports. The micro-filter isolates the fluid inside the valve from contamination. The micro-filter is cleaned by purging fluid before and after sample collection. The distribution valve may include a sterile filter. The distribution valve may include a dispensing pump. The distribution valve is used to access fluid from a fluid line to determine the concentration of at least one analyte, wherein said line is used with a tube originating from a vascular access point, a pump fixedly attached to the tube, a valve fixedly attached to the tube and located above the pump mechanism, at least one measurement element, and an electronic meter. 
         [0027]    In another embodiment, the disclosed inventions are used with an automated blood glucose analysis device further comprising an access device for gaining access to blood with a catheter; a pump to withdraw blood from the patient in a predetermined schedule; at least one sensor placed in contact with said blood by an action of the fluid access interfaces of the present invention; and a signal processor to measure a signal produced by the at least one sensor upon contact with said blood where the signal is indicative of said at least one predetermined parameter. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0028]    These and other features and advantages of the present invention will be appreciated, as they become better understood by reference to the following Detailed Description when considered in connection with the accompanying drawings, wherein: 
           [0029]      FIGS. 1A and 1B  are illustrations of one embodiment of the fluid access interface device of the present invention, implemented as a flexible tube; 
           [0030]      FIG. 2  depicts another embodiment of the fluid access interface device of the present invention; 
           [0031]      FIGS. 3A ,  3 B, and  3 C illustrate the structure and operational steps of one embodiment of the fluid access interface device of the present invention; 
           [0032]      FIG. 4  illustrates another embodiment of the fluid access interface device of the present invention implemented as a transfer tube with an integrated test strip holder; 
           [0033]      FIG. 5  illustrates a lancet structure; 
           [0034]      FIGS. 6A ,  6 B,  6 C,  6 D, and  6 E depict the structure and operational steps of one embodiment of the fluid access interface of the present invention implemented as a transfer tube with one closed end; 
           [0035]      FIG. 7  depicts another embodiment of the fluid access interface of the present invention implemented as a transfer tube equipped with a micro-syringe on one end; 
           [0036]      FIGS. 8A ,  8 B,  8 C, and  8 D depict the structure and operational steps of one embodiment of the fluid access interface device of the present invention wherein a pump is employed; 
           [0037]      FIG. 9  is a cross-sectional view of one embodiment of the fluid access interface of the present invention implemented as a transfer tube equipped with a pump; 
           [0038]      FIGS. 10A ,  10 B, and  10 C depict the structure and operational steps of one embodiment of the fluid access interface of the present invention wherein a shuttle and dual needle-less port are employed; 
           [0039]      FIG. 11A and 11B  depict the structure and operational steps of one embodiment of the fluid access interface of the present invention implemented as an air jet fluid access port; 
           [0040]      FIGS. 12A and 12B  depict the structure and operational steps of one embodiment of the fluid access interface of the present invention wherein a distribution valve is employed; 
           [0041]      FIGS. 13A and 13B  depict the structure and operational steps of another embodiment of the fluid access interface of the present invention, implemented as a distribution valve equipped with a filter; 
           [0042]      FIGS. 14A ,  14 B,  14 C, and  14 D depict the structure and operational steps of one embodiment of the fluid access interface of the present invention implemented as a distribution valve with an integrated dispensing pump; 
           [0043]      FIG. 15  is a schematic diagram of an exemplary embodiment of an automated blood parameter testing apparatus for use with the present invention; and 
           [0044]      FIG. 16  is a schematic diagram of another exemplary embodiment of an automated blood parameter testing apparatus for use with the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0045]    The present invention is directed towards an integrated, automated system for measurement and analysis of blood analytes and blood parameters. The present invention is also directed towards an automated blood parameter testing apparatus portion of the automated blood parameter analysis and measurement system. More specifically, the present invention is directed towards methods, apparatuses, and systems for accessing a blood sample, present in a vascular access line connected to a patient or any other form of tubing via a fluid access interface. In one embodiment, the fluid access interface methods, apparatuses, and systems are used for automated blood glucose testing. 
         [0046]    In automatic operation, when fluid sampling is initiated, either by a pre-determined, programmed schedule or via operator input, the fluid access interface is activated and a fluid sample is drawn from the vascular access line connected to a patient or any other form of tubing. The system operates automatically to draw the fluid samples via a fluid access interface at suitable, programmable frequencies to analyze the drawn blood samples and obtain the desired blood readings such as glucose levels, hematocrit levels, hemoglobin blood oxygen saturation, blood gasses, lactates or any other parameter as would be evident to persons of ordinary skill in the art. 
         [0047]    As referred to herein, the terms “blood analyte(s)” and “blood parameter(s)” refers to such measurements as, but not limited to, glucose level; ketone level; hemoglobin level; hematocrit level; lactate level; electrolyte level (Na + , K + , Cl − , Mg 2+ , Ca 2+ ); blood gases (pO 2 , pCO 2 , pH); cholesterol; bilirubin level; and various other parameters that can be measured from blood or plasma samples. The term “vascular access point(s)” refer to venous or arterial access points in the peripheral or central vascular system. 
         [0048]    Reference will now be made in detail to specific embodiments of the invention. While the invention will be described in conjunction with specific embodiments, it is not intended to limit the invention to one embodiment. Thus, the present invention is not intended to be limited to the embodiments described, but is to be accorded the broadest scope consistent with the disclosure set forth herein. 
         [0049]    In one embodiment, the present invention is a device for accessing a blood sample from a patient and measuring blood constituents, wherein the fluid access interface comprises a flexible transfer tube having a shape, wherein the transfer tube is used to provide a direct fluid flow path to a test substrate and wherein an alteration in the shape of the tube causes the tube to move from an open state to a closed state. In an open state, the test tube substrate provides a blood sample to a proximally located testing site, such as a testing strip or sensor. 
         [0050]      FIGS. 1   a  and  1   b  are illustrations of one embodiment of the fluid access interface of the present invention, wherein the flexible tube is employed. In a first embodiment, a fluid access interface is implemented as a flexible tube. Specifically,  FIG. 1   a  is a depiction of flexible tube  100  wherein outlet  101  is in a closed state.  FIG. 1   b  is a depiction of a bent flexible tube  100  wherein outlet  102  is in an open state. An alteration in the shape of the tube facilitates control of the outlet. The alteration of the tube shape can be facilitated by a member  103 , which can be any structure, including a rod, stick, lever, or any linear extension. When flexible tube  100  is bent, as shown in  FIG. 1   b , the tube is split open, creating an open state and thus forming an outlet for a fluid sample. In an open state, outlet  102  may comprise a slit or hole, however, the opening is not limited to such configurations. 
         [0051]      FIG. 2  depicts another embodiment of a fluid access interface  200  wherein a transfer tube is employed. A fluid access interface is implemented as a transfer tube equipped with a cap or valve, used to extract fluid from a vascular access line connected to a patient or any other form of tubing. As shown in  FIG. 2 , the main fluid line  201  further comprises transfer tube  202 , and end valve  203 . In one embodiment, main fluid line  201  is a vascular access line connected to a patient. Preferably, transfer tube  202  is smaller in diameter than main fluid line  201 . End valve  203  is used to draw fluid into transfer tube  202  for subsequent collection. When the transfer tube  202  is not in use, end valve  203  may serve as a cap, thus providing a sealed, sterile barrier. 
         [0052]      FIGS. 3   a ,  3   b , and  3   c  illustrate the structure and operational steps of another embodiment of the fluid access interface of the present invention wherein a transfer tube is employed. As shown in  FIG. 3   a , the fluid access interface device  300  of the present invention is implemented as a transfer tube that is used to remove fluid from a main fluid line  305  connected to a patient. Main fluid line  305  further comprises seal  301 . In one embodiment, seal  301  is a needle-less access port. The transfer tube  302  is positioned to come into contact with seal  301 , extract a fluid sample (not shown) from main line  305 , and subsequently deliver the fluid sample to a test substrate  303 . 
         [0053]      FIG. 3   b  illustrates fluid access interface device  300  in operation. The transfer tube  302  penetrates seal  301 , accessing main fluid line  305 . The transfer tube  302  is thus used to provide a direct flow path to the test substrate  303 . As shown in  FIG. 3   c , after single use transfer tube  302  comes into contact with main fluid line  305 , and more specifically, seal  301 , transfer tube  302 , now containing fluid, is extracted from seal  301 . Single use transfer tube  302  subsequently transports fluid to the test substrate  303 . After removal from the test unit, transfer tube  303  is disposed into an appropriate container. 
         [0054]      FIG. 4  illustrates another embodiment of a fluid access interface device  400  wherein a transfer tube  402  is integrated with a test strip holder  404 . The integrated transfer tube  402  and test strip holder  404  is employed to access a fluid sample present in a vascular access line [not shown] connected to a patient or any other form of tubing. As previously shown, the main fluid line or vascular access line is preferably accessed via a needle-less port or seal. The integrated transfer tube  402  and test strip holder  404  is employed to position the test substrate  403  for proper fluid dispensing and mechanical handling. In one embodiment, the device  400  minimizes the amount of fluid required in a sample by reducing the dead volume of the structure and is optimally designed so that fluid flow is not impeded. Device  400  is also optimally shaped to effectuate capillary flow. Excess fluid resides in the area around the test substrate and single use transfer tube. The operation of the transfer tube has already been described with respect to  FIG. 3  and will not be repeated herein. In operation of device  400 , the fluid is delivered to the test substrate  403  via the transfer tube  402 . 
         [0055]      FIG. 5  illustrates a portion of one embodiment of a fluid access interface designed to access a blood sample through the skin of a person. Lancet  500  is used to access a blood sample by using sharp protusion  501  to enter through a patient&#39;s skin. Sharp protusion  501  is physically integrated with edge  504  that is attached to structure  502 . Structure  502  comprises a curved base  506  and two faces  505  curved to conform to the shape of the curved base  506  and having a linear top side. Integrally formed with the structure  502  are handles  503  which are flattened protusions designed to allow a person or mechanical actuator to hold and push the sharp protusion  501  into a patient&#39;s skin. 
         [0056]      FIGS. 6   a ,  6   b ,  6   c ,  6   d , and  6   e  illustrate the operational steps of one embodiment of the fluid access interface device of the present invention implemented as a transfer tube with a closed end forming a bulb. As shown in  FIG. 6   a , device  600  is a fluid access interface for accessing a blood sample, present in a main fluid line connected to a patient or any other form of tubing. In one embodiment, the fluid access interface  600  accesses the fluid sample from a needle-less access port or seal  601  attached to main fluid line  602 . The fluid sample is subsequently delivered to test substrate  603 . In one embodiment, fluid access interface device  600  comprises a transfer tube  604  with closed end  605 , which is flexible and can be expanded and contracted to access a fluid sample and subsequently deposit the sample on a test substrate. 
         [0057]    As shown in  FIG. 6   b , in operation, transfer tube  604  of device  600  is used to penetrate the needle-less access port or seal  601  of main fluid line  602 . Now referring to  FIG. 6   c , closed end  605  of device  600  is expanded, thus withdrawing a fluid sample. As shown in  FIG. 6   d , the device is removed from the needle-less access port  601  and positioned on the test substrate  603 . Finally, as shown in  FIG. 6   e , the closed end  605  of the device  600  is contracted depositing the fluid on the test substrate. 
         [0058]      FIG. 7  depicts one embodiment of the fluid access interface of the present invention implemented as a transfer tube equipped with a micro-syringe on one end. The fluid access interface is employed to access a fluid sample, present in a main fluid line connected to a patient or any other form of tubing. In one embodiment, the fluid access interface  700  accesses the fluid sample from a needle-less access port (not shown) attached to the main fluid line (not shown) and delivers the fluid sample to a test substrate using a plunger-type device that regulates fluid volume. Device  700  comprises two ends—a distal end  701  and a proximate end  702 . Proximate end  702  is preferably sized and shaped to penetrate a needle-less access port (not shown). Distal end  701  further comprises plunger  703 , which is pulled and pushed to remove and deposit the fluid sample on the test substrate. Fluid access interface device  700  is similar in operation to the device described above with respect to  FIG. 6  and thus, operational characteristics will not be repeated herein. 
         [0059]      FIGS. 8   a ,  8   b ,  8   c , and  8   d  illustrate the structure and operational steps of one embodiment of the fluid access interface of the present invention. The fluid access interface, implemented as a piston pump, is employed to access a fluid sample, present in a main fluid line connected to a patient or any other form of tubing. In one embodiment, the fluid access interface  800  accesses the fluid sample from a needle-less access port or seal attached to the main fluid line and delivers the fluid sample to a test substrate. 
         [0060]    Referring now to  FIG. 8   a , a fluid sample is transferred from main fluid line  801  to a test substrate  802 , via fluid access interface  800 . In one embodiment, fluid access interface  800  comprises piston  805 . Piston  805  further comprises piston chamber  805   a  and piston pump  805   b.  Piston  805  is employed to draw a bolus of fluid (not shown) from the main fluid line  801  into a cylinder  806 , as shown in  FIG. 8   b . As shown in  FIG. 8   c , the bolus of fluid is then transported to the opening of test port  807  through cylinder  806 . The bolus of fluid is then pushed to test substrate  802 , as shown in  FIG. 8   d . Fluid access interface  800  may be implemented in several configurations, including, but not limited to multiple-use or single-use and/or with a multiple device configuration, such as a stack. 
         [0061]      FIG. 9  is a cross-sectional view of one embodiment of the fluid access interface device of the present invention wherein a transfer tube further comprising a piston pump is employed to access a fluid sample, present in a main fluid line connected to a patient or any other form of tubing. In one embodiment, the fluid access interface  900  accesses the fluid sample from a needle-less access port or seal attached to the main fluid line and delivers the fluid sample to a test substrate. 
         [0062]    Fluid access interface device  900  comprises a transfer tube  901  and pistons  902  and  903 . Pistons  902  and  903  draw a bolus of fluid from main fluid line  904  via transfer tube  901  into a cylinder  905 . The drawn bolus of fluid is then transported alongside cylinder  905  to the test access port entrance  906  and subsequently pushes the fluid through to test substrate  907 . Device  900  can be employed in many configurations, including, but not limited to multiple-use or single-use with a multiple device configuration, such as a stack. 
         [0063]      FIGS. 10   a ,  10   b , and  10   c  depict the structure and operational steps of one embodiment of the fluid access interface of the present invention. The fluid access interface  1000  is employed to access a fluid sample, present in a main fluid line connected to a patient or any other form of tubing. In one embodiment, the fluid access interface  1000  accesses the fluid sample from a dual-sided needle-less access port or seal  1004  attached to the main fluid line  1001  via shuttle  1003  and delivers the fluid sample to a test substrate [not shown]. 
         [0064]    Referring to  FIG. 10   a , apparatus  1000  is used to transfer a fluid sample from main fluid line  1001  to test substrate  1002 . Shuttle device  1003  is employed to penetrate first membrane  1004   a  of the dual-sided needle-less port or seal  1004  and access fluid. As shown in  FIG. 10   b , shuttle device  1003  passes into first membrane  1004   a  of dual-sided needle-less port or seal  1004  and collects a fluid sample. Shuttle device  1003  then passes through second membrane  1004   b  of dual-sided needle-less port or seal  1004  and delivers the sample to test substrate  1002 , as shown in  FIG. 10   c . Shuttle device  1003  is a single-use device employed to facilitate a sanitary and uncontaminated fluid sample without passing back through the sample port. 
         [0065]      FIGS. 11   a  and  11   b  illustrate the structure and operational steps of another embodiment of the fluid access interface of the present invention wherein an air jet fluid access port is employed. The fluid access interface is used to access a fluid sample, present in a main fluid line connected to a patient or any other form of tubing. In one embodiment, the fluid access interface  1100  accesses the fluid sample from an air jet fluid access port attached to the main fluid line and delivers the fluid sample to a test substrate. Fluid access interface device  1100  comprises valve  1103  used to remove a volume of fluid from the main fluid line  1101  through an exit port  1107  to a substrate  1102 . Valve  1103  rotates from a first state, shown in  FIG. 11   a , to a second state, shown in  FIG. 11   b , which aligns a collected sample with exit port  1107  and air pump inlet  1109 . A low volume air pump  1104  then pushes the fluid sample through the inlet  1109  onto the test substrate  1102 , as shown in  FIG. 11   b . A micro-filter  1105  is preferably employed to ensure that no contamination enters the system or the fluid sample. Valve  1103  then returns to the first state from the second state after disbursing the blood sample on substrate  1102 . 
         [0066]      FIGS. 12   a  and  12   b  depict the structure and operational steps of another embodiment of the fluid access interface of the present invention wherein a distribution valve is used. The fluid access interface is employed to access a fluid sample, present in a main fluid line connected to a patient or any other form of tubing. Fluid access interface  1200  accesses the fluid sample from the main fluid line  1201  and delivers the fluid sample to a test substrate  1202 . As shown in  FIG. 12   a , device  1200  comprises a by-pass distribution valve  1203 , employed to access fluid from main fluid access line  1201  and deliver it to test substrate  1202 . Valve  1203  is used to divert fluid flow to a side path  1205 , as shown in  FIG. 12   b . The fluid sample is then pushed onto the test substrate  1202  via the side path with a pump (not shown). 
         [0067]      FIGS. 13   a  and  13   b  illustrate the structure and operational steps of another embodiment of the fluid access interface of the present invention wherein the distribution valve shown in  FIG. 12  is further equipped with a sterile filter. The operational steps are similar to those described in detail with respect to  FIG. 12 . The details will only be described herein where necessary to differentiate this embodiment from that described with respect to  FIG. 12 . 
         [0068]    Referring now to  FIG. 13   a , device  1300  is employed to access fluid from main fluid line  1301  and deliver the fluid sample to test substrate  1302 . Valve  1303  is used to divert the flow of fluid from main fluid line  1301  to a side path  1305 . Pump [not shown] is then used to push the fluid sample onto a test substrate  1302 . Valve  1303  also contains an opening  1307 , where the fluid sample exits to contact the test substrate  1302 . At opening  1307 , device  1300  further comprises micro-filter  1308  through which the fluid sample passes prior to coming into contact with test substrate  1302 . Micro-filter  1308  serves to protect the fluid inside valve  1303  from contamination.  FIG. 13   b  illustrates the fluid sample coming into contact with the test substrate  1302 . In one embodiment, micro-filter  1308  is cleaned via purging clean fluid (not blood) before and after sample collection onto a “purge pad” (not shown) for disposal. The micro-filter  1308  is cleaned when the valve  1303  is rotated back to “by-pass flow” position. 
         [0069]      FIGS. 14   a ,  14   b ,  14   c , and  14   d  depict the structure and operational steps of one embodiment of the fluid access interface of the present invention employing a distribution valve, such as that shown in  FIGS. 12 and 13 , further equipped with an integrated dispensing pump. As shown in  FIG. 14   a , device  1400  is used to access fluid from a main fluid line  1401  and deliver the fluid sample to a test substrate  1402 . As shown in  FIG. 14   b , plunger  1403  on an internal pump (not shown) is pulled to obtain a fluid sample. Valve  1404  is rotated to divert the main flow of fluid to a side path, as shown in  FIG. 14   c . The fluid sample is subsequently pushed onto the test substrate  1402  with plunger  1403 , as depicted in  FIG. 14   d . 
         [0070]      FIG. 15  illustrates one embodiment of an exemplary automated blood parameter testing apparatus for use with the fluid access interface of the present invention. U.S. patent application Ser. No. 11/157,110, assigned to Applicant, is herein incorporated by reference. The invention therein is directed towards an automated blood parameter testing apparatus in which a blood parameter measurement element is employed. 
         [0071]    As shown in  FIG. 15 , in one exemplary embodiment, the various embodiments of the fluid access interface of the present invention are used with an automated blood parameter testing apparatus  1500 . In one embodiment, the automated blood parameter testing apparatus is a glucose meter  1504 . In another embodiment, the blood parameter testing apparatus  1500  is used with any one of the fluid access interfaces  1508  disclosed herein. In one embodiment, a glucose testing strip  1503  is in fluid communication with the fluid access interface  1508 . The fluid is moved from infusion bag  1502  into a patient [not shown] and blood samples are retrieved from a patient using a pump  1501 , preferably a syringe pump. A plurality of valves  1505  may be used to control fluid flow from either the infusion bag  1502  or patient [not shown]. The automated device  1500  is programmable to initiate a sample reading periodically or via operator input. Operator input is initiated by, but not limited to, the push of a button. In addition, operator input may be initiated at the central monitoring station. 
         [0072]      FIG. 16  illustrates another embodiment of an exemplary automated blood parameter testing apparatus for use with the fluid access interface of the present invention. U.S. patent application Ser. No. 11/048,108, assigned to Applicant, is herein incorporated by reference. The invention therein is directed towards an automated blood parameter testing apparatus in which a blood parameter measurement element is employed. 
         [0073]    As shown in  FIG. 16 , in one exemplary embodiment, the various embodiments of the fluid access interface of the present invention are used with an automated blood parameter testing apparatus  1600 . It is to be understood that such embodiment is exemplary, but not limiting, and that the automated blood analysis device  1600  may be connected to other external devices at the same vascular access point. Automated blood analysis device  1600  blocks the operation of any connected infusion and/or external device (such as an external pressure transducer) during the period of blood sampling, in order to ensure that the blood sample is not diluted/altered by other fluids injected in the patient. 
         [0074]    During normal operation, pump  1611  drives fluid from infusion bag  1609  through a main line  1650  and into the patient  1602 . A first stopcock  1617  blocks fluid from traveling out of the main line  1650  and is periodically opened to permit an external infusion, manual blood sampling, or the measurement of pressure using an external transducer. 
         [0075]    When performing automated blood sampling and measurement of required blood analytes, main unit  1603  directs pump  1611  to reverse, thereby reversing the flow of fluid. Main unit  1603  communicates with the valve  1617 , pump  1611 , and sensor cassette  1605  using internal links  1633  which can be wired or wireless. It further communicates to external monitoring stations using external link  1635 . Once the pump  1611  reverses operation, blood is pulled from patient  1602  into the main line  1650 . The blood is drawn along the tube until the remaining infusion volume and the initially diluted blood volume passes fluid access interface  1618  which is proximate to sensor cassette  1605 . A pressure measurement element can be used to ensure pressure does not increase excessively. 
         [0076]    Main unit  1603  calculates the required volume of blood to be withdrawn based on the diameter and length of the tubing and according to a programmable dead-space volume, which can be either pre-calibrated or user-defined. Optionally, a blood presence sensor  1620  can be used to establish whether undiluted blood has reached the tube segment proximal to the fluid access interface  1618 . When undiluted blood reaches the fluid access interface  1618 , the fluid access interface is activated to obtain an undiluted blood sample for measurement by the sensor cassette  5 . The fluid access interfaces disclosed herein may be used obtain the undiluted blood samples. 
         [0077]    When the undiluted blood sample is taken inside sensor cassette  1605  (by fluid access interface mechanism  1618 ), a sensor (from a plurality of sensors within sensor cassette  1605 ) is placed into contact with the drawn blood sample. Sensor is preferably, but not limited to, a single use sensor, and is used to measure patient blood analyte(s) and blood parameter(s). Sensor is preferably a component of a manual test device, such as, but not limited to glucose test strips for measuring glucose levels. 
         [0078]    While the blood sample is analyzed, blood withdrawal from patient  1602  is stopped and main unit  1603  reverses the operation of pump  1611 . The tubing components, including line  1650 , are then flushed by purging fluid from fluid bag  1609 . The remaining blood in line  1650  may be infused back into patient  1602 . 
         [0079]    Single use sensors are preferably packaged into disposable cassette  1605  and replaced periodically. Sensor cassette  1605  is preferably sterile, and is also preferably disposed after use with a single patient  1602 . Sensor cassette  1605  supports at least one or a plurality of single use sensors that are advanced sequentially and positioned for direct contact with the drawn blood sample. After completing a measurement, the used sensor is automatically advanced from the measurement location to a location for disposed sensors. Between measurements, the system moves a new sensor forward into contact with fluid access interface  1618 , thus replacing the one used in the previous measurement. Various cassette sizes can be manufactured and sensor cassette  1605  can be available, but is not limited to 25, 50, or 100 measurement capacities. In one design, sensor cassette  1605  also stores the consumed test supplies and sample waster. 
         [0080]    The use of single-use sensors (similar to the use of finger stick sensors) eliminates the need for time-consuming operator-directed calibration procedures. In particular, each sensor cassette  1605  can be factory pre-calibrated. Optionally, sensor cassette  1605  or plurality thereof and individual sensors  1619  of the same type have the same pre-calibration values. Main display and control unit  1603  can automatically read the cassette factory calibration values by standard means well-known to those of ordinary skill in the art, such as by reading the data from a barcode or an EPROM embedded in sensor cassette  1605 . Optionally, factory values may be entered manually. 
         [0081]    In addition, sensor cassette  1605  may be hermetically sealed and/or include humidity controls means, such as, but not limited to a small bag of dessicant material. In another option, each sensor or a portion thereof, may be contained in a packaging that is automatically opened prior to measurement. Optionally, the measurement portion of the sensors can be covered with a thin layer that protects the reagent area against moisture and/or light during storage (particularly useful for both electrochemical and optochemical sensors). The thin protective layer can be automatically peeled off by a peeling element (not shown), prior to the sensor being placed in position for measurement. The peeling element may comprise, but is not limited to, an edge-knife element strategically placed inside sensor cassette  1605 . 
         [0082]    When using electrochemical sensors, sensor cassette  1605  includes an electronic interface to main unit  1603  of automated blood analysis device  1600 . When using optochemical or optical sensors, an electronic interface is optional, and sensor cassette  1605  can be designed to work with only a opto-mechanical interface to main unit  1603 . In another embodiment, sensor cassette  1605  may optionally include a small battery power supply in case of power failure. 
         [0083]    In one embodiment, sensor cassette  1605  may be either attached or inserted into main unit  1603 . In the alternative, main unit  1603  may include an external sub-unit (not shown) that serves as the receiving interface for sensor cassette  1605 . Thus, sensor cassette  1605  can be placed in proximity to patient  1602  without limiting the size of main unit  1603 . In another embodiment, sensor cassette  1605  may optionally be attached to main unit  1603  by means of a data connector, an optional power connection means, and tubing. 
         [0084]    The above examples are merely illustrative of the many applications of the system of present invention. Although only a few embodiments of the present invention have been described herein, it should be understood that the present invention might be embodied in many other specific forms without departing from the spirit or scope of the invention. Therefore, the present examples and embodiments are to be considered as illustrative and not restrictive, and the invention is not to be limited to the details given herein, but may be modified within the scope of the appended claims.