Patent Publication Number: US-2003224523-A1

Title: Cartridge arrangement, fluid analyzer arrangement, and methods

Description:
TECHNICAL FIELD  
     [0001] This disclosure describes cartridges for analysis of fluid samples, wherein the cartridge is for use with an analyzer device. In specific applications, this disclosure describes cartridges, arrangements, and methods for analyzing blood including, for example, blood gases, blood electrolytes, glucose, blood urea nitrogen, and creatinine.  
     [0002] This disclosure is an on-going development of Diametrics Medical, Inc., the assignee of this disclosure. This disclosure concerns continuing developments related, in part, to the subject matter characterized in U.S. Pat. Nos. 5,325,853; 6,066,243; 5,384,031; 5,223,433; 6,060,319; and 5,232,667. Each of the patents identified in the previous sentence is also owned by Diametrics Medical, Inc., and the complete disclosure of each is incorporated herein by reference. 
    
    
     
       BACKGROUND  
       [0003] Blood gas determinations, including the partial pressures of oxygen (pO 2 ), carbon dioxide (pCO 2 ), acidity or alkalinity (pH), and concentration of certain electrolyte species such as potassium (K + ) in the blood are examples of measurements useful for diagnosis. It can be particularly useful to have quick blood analysis (e.g., within a few minutes of withdrawing blood from the patient) in order to diagnose and treat the patient.  
       [0004] Improvements in blood analysis technology are desirable.  
       SUMMARY  
       [0005] A cartridge for analysis of fluid samples useable with an analyzer device is provided. The cartridge includes an arrangement to selectively control fluid flow within the cartridge.  
       [0006] One type of cartridge includes a fluid channel. A sensor arrangement is oriented within the fluid channel and includes at least one dry-stored sensor and at least one wet-stored sensor. The cartridge may include a first port. In some instances, the cartridge can include a second port. In some instances, the cartridge can include a third port.  
       [0007] In some implementations, a cartridge includes a fluid reservoir in fluid communication with a port on the cartridge. The fluid reservoir defines a fluid passage and a fluid dispenser actuator. The actuator includes an over-center engageable button depressible to initiate fluid flow from an internal volume in the fluid reservoir and through the fluid passage and through the port into the sensor arrangement on the cartridge.  
       [0008] Methods for analyzing fluid samples, calibrating sensors, and using cartridges are provided. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0009]FIG. 1 is a schematic depicting a general environment of use utilizing principles of this disclosure;  
     [0010]FIG. 2 is a perspective view of a cartridge and an analyzer device constructed according to principles of this disclosure;  
     [0011]FIG. 3 is a schematic, top plan view of the cartridge depicted in FIG. 2, and constructed according to principles of this disclosure;  
     [0012]FIG. 4 is a schematic, side elevational view of the cartridge of FIG. 3, and including a syringe mounted thereon;  
     [0013]FIG. 5 is a schematic view of a fluid channel and valve arrangement used in the cartridge of FIGS. 2 and 3, each of the valves in the valve arrangement being in a closed position;  
     [0014]FIG. 6 is a view similar to FIG. 5, and showing one of the valves in an open position and another of the valves in a closed position;  
     [0015]FIG. 7 is a view similar to FIGS. 5 and 6, but showing a different state of the valve arrangements;  
     [0016]FIG. 8 is a schematic, cross-sectional view of a fluid reservoir having a fluid dispenser actuator, utilized in a preferred embodiment of the cartridge of FIGS. 2 and 3;  
     [0017]FIG. 9 is a view similar to FIG. 8, but showing the actuator in a depressed position;  
     [0018]FIG. 10 is a perspective view of a base structure of the fluid reservoir depicted in FIGS. 8 and 9;  
     [0019]FIG. 11 is a top plan view of the base structure depicted in FIG. 10;  
     [0020]FIG. 12 is a cross-sectional view of the base structure, the cross-section being taken along the line  12 - 12  of FIG. 11;  
     [0021]FIG. 13 is a top plan view of a lid for the fluid reservoir of FIGS. 8 and 9, the lid being mountable on the base structure of FIGS.  10 - 12 ; and  
     [0022]FIG. 14 is a cross-sectional view of the lid of FIG. 13, the cross-section being taken along the line  14 - 14  of FIG. 13. 
    
    
     DETAILED DESCRIPTION  
     A. Environment of Use and General Overview  
     [0023]FIG. 1 depicts one example of an environment of use for the principles described in this disclosure. In FIG. 1, there is a medical treatment system at  20 . A patient  22  is shown lying in a bed  23  adjacent to an analyzer device  24 . The medical treatment system  20  may be in, for example, a hospital room, an operating room, or other patient treatment facilities. The analyzer device  24  is useable for determining characteristics of fluid samples from the patient  22 . For example, body fluid including, e.g. blood, may be drawn from the patient  22  and analyzed bedside by the analyzer device  24  to obtain characterization information. The analyzer device  24  can analyze the fluid sample to determine, for example, oxygen content, creatinine content, blood urea nitrogen (BUN) content, glucose content, sodium content, acidity (pH), carbon dioxide content, calcium content, potassium content, hematocrit content, chloride content, lactate content, coagulation, and other desired information, depending upon the particular application.  
     [0024] The fluid sample is drawn from the patient  22  and placed into a container or cartridge  26 . The cartridge  26  is then oriented within the analyzer device  24 , which analyzes the fluid sample, and the results are provided to the caregiver. This “point of care” diagnostic fluid testing reduces turn-around time, improves clinical protocols and staff efficiency, and contributes to improved patient outcomes when compared to existing prior art systems. Such prior art systems include hospital laboratory equipment that is permanently installed.  
     [0025] In certain applications, the analyzer device  24  includes a blood analysis system as described in U.S. Pat. No. 6,066,243, incorporated herein by reference. One type of useable analyzer device  24  is commercially available from Diametrics Medical Inc., Roseville, Minn., under the brand name IRMA Blood Analysis System.  
     [0026] In some applications, the analyzer device  24  is insertable into or otherwise connected to a patient monitor  28 , depicted in phantom lines. The monitor can be, for example, a Philips CMS and V 24 /V 26  hospital monitor system. Monitor  28  is integrated with other information from the patient  22  in a main database  30 . In this type of application, the analyzer device  24  is a blood analysis system compatible with plugging into a hospital monitor  28 , such as the system commercially available from Diametrics Medical under the brand name PORTAL.  
     [0027] In FIG. 2, there is a perspective view of an analyzer device  31  and cartridge  26 . In FIG. 2, cartridge  26  is shown removed from analyzer device  31 . The cartridge  26  is pluggable or insertable into the analyzer device  31  at the cartridge receiving area  32 . The analyzer device  31  includes an external housing  34 , which, in the particular one depicted in FIG. 2, forms a carrying handle  36 . The handle  36  defines an opening  38  sized for receipt of a human hand, contributing to the portable nature of the analyzer device  31 . The analyzer device  31  usually will weigh less than 50 lbs, and typically less than 25 lbs, also contributing to portability. In the one shown, the analyzer device  31  includes an output display  40  and a battery case  42 . In some instances, the device  31  can include a printer system (not shown).  
     B. Some Problems With Existing Systems  
     [0028] To determine characteristics of a fluid utilizing principles of this disclosure, selected sensors are utilized to measure the characteristic of interest. Sensors come in various types. For electrochemical sensors, typical types of sensors used are: ion selective electrode (potentiometric) sensors; amperometric sensors; conductometric sensors; and enzymatic sensors.  
     [0029] If the fluid sample is blood, for example, for measuring blood gases, typical useable constructions may include ion selective electrode sensors to measure pH and pCO 2 . One type of pO 2  sensor may be an amperometric sensor. For blood electrolytes, for example, sodium (Na + ) sensors, calcium (iCa ++ ) sensors, and potassium (K + ) sensors can be ion selective electrode sensors. Hematocrit may be measured using, for example, a conductometric sensor. Chloride may be measured, in many typical implementations, with an ion selective electrode sensor. Glucose, blood urea nitrogen (BUN), and creatinine may be measured utilizing, for example, enzymatic sensors. To measure blood coagulation, one type of sensor useable may be a conductometric sensor.  
     [0030] In order to obtain an accurate measurement, in some instances, selected ones of the sensors should be calibrated. U.S. Pat. No. 5,325,853, incorporated by reference herein, describes systems and methods for calibrating certain of these types of sensors. The calibration systems described in the &#39;853 patent utilize a gel stabilized dispersion or solution of aqueous and/or non-aqueous calibration material. In such systems and methods in the &#39;853 patent, the calibration gel is stored over the sensors until the cartridge is used for analyzing the fluid sample. Typically, the calibration gel is placed over the sensors in the manufacturing facility, and after calibration by the user by inserting the cartridge into analyzer device  24 , the gel is pushed aside into a waste chamber to make room for the fluid, in this case, blood.  
     [0031] Certain types of calibration problems may be encountered when enzymatic sensors have calibrant stored thereon. For example, in some methods, the presence of the enzymes within the sensor membranes will deplete the analytes within the calibrant gel and thereby change the concentration of the analyte within the calibrant.  
     [0032] It is desirable to store certain sensor types before use in either a solution (“wet-stored”) or not in a solution (“dry-stored”). When more than one sensor type is desired within a single cartridge, and certain of the sensors are to be wet-stored, while certain of the sensors are to be dry-stored, there can be complications.  
     [0033] Thus, systems and methods for calibrating selected ones of the sensors contained within a single cartridge, no matter what the type of calibration method (for example, with a liquid calibrant or not with a liquid calibrant) are useful. A cartridge that can accommodate a variety of sensors, regardless of the storage requirement (wet or dry) and regardless of the way it is calibrated is useful. Further, it is useful to have a cartridge that is easy to manufacture due to a non-complex flow channel and that can perform most of its sensing by utilizing just a single fluid sample injection therein.  
     C. Example Cartridges, FIGS.  3  and  4   
     [0034]FIG. 3 illustrates, schematically, a plan view of one example cartridge  26 . The cartridge  26  includes a base structure  50 , preferably constructed of a polymer material such as a polycarbonate. The base structure  50  holds or is a housing for a substrate  52 . In preferred applications, the substrate  52  is a ceramic substrate.  
     [0035] The base structure  50  defines at least one fluid channel  54 , which accommodates a sensor arrangement  56  therein. By “sensor arrangement”, it is meant at least one sensor or a plurality of sensors is contained within the fluid channel  54 . The sensors within the sensor arrangement  56  can be any of the sensor types discussed above, including, for example, wet-stored, dry-stored, liquid-calibrated, non-liquid calibrated, or not calibrated at all. In some systems, there may be additional sensor types within the sensor arrangement  56 .  
     [0036] The cartridge  26  further includes a conductor arrangement  58  in electrical contact with the sensor arrangement  56 . The conductor arrangement  58 , in the one shown, includes an array of functional electrical conductors  60 . The conductors  60  allow for electrical communication between the cartridge  26  and the analyzer device  24 , and include input and output conductors. The conductors  60  are constructed in accordance with conventional techniques. In the example shown, they are deposited on the surface of the substrate  52 . As can be seen in FIGS. 3 and 4, the conductors  60  are adjacent to an edge  62  of the cartridge  26 , allowing the cartridge  26  to be adaptable in use with edge connectors.  
     [0037] The cartridge  26  includes a port arrangement  64  in fluid communication with the fluid channel  54 . The port arrangement  64  allows for selective insertion of selected fluids into the fluid channel  54 . In the example shown in FIG. 3, the port arrangement includes at least a first port  66  that provides fluid communication between a first fluid reservoir  68  and the fluid channel  54 . In preferred systems, there will also be an arrangement to prevent fluid from flowing from the fluid channel  54  through the first port  66  in a direction toward the first fluid reservoir  68 .  
     [0038] The port arrangement  64  may further include, and does so in the one depicted, a second port  70 . The second port  70  allows for fluid communication between a second fluid reservoir  72  (FIG. 4) and the fluid channel  54 . In the particular one shown in FIG. 4, the second fluid reservoir  72  is a syringe  74 , which can have a luer lock  76  for a reliable connection between the syringe  74  and the cartridge  26 . In certain systems, there may be an optional locking arrangement to prevent fluids from flowing from the fluid channel  54  back through the second port  70  toward the second fluid reservoir  72 .  
     [0039] Depending upon the types of sensors desired in the sensor arrangement  56 , the port arrangement  64  may also include a third port  78 . The third port  78  allows for fluid flow from a duct  80  into the fluid channel  54 . There may also be an optional arrangement to prevent fluid from flowing from the fluid channel  54  back through the third port  78  and through the duct  80  (explained below in connection with a septum  114 ). Note that the third port  78  is not viewable in the side view of FIG. 4, but can be seen from the top view of FIG. 3.  
     [0040] The cartridge  26  shown further includes a waste chamber  82  in fluid communication with the fluid channel  54 . In use, the waste chamber  82  collects and contains used fluids in the cartridge  26 . Such used fluids include, for example, used calibration fluid and bodily fluid, such as blood.  
     [0041] As described above, the sensor arrangement  56  can include just one sensor, or a plurality of sensors. Further, the sensor arrangement  56  can include different types of sensors including ion selective electrode sensors, amperometric sensors, conductometric sensors, and enzymatic sensors. The sensor arrangement  56  can include sensors that are calibrated by being covered with calibration liquid or sensors calibrated by other methods that do not involve calibration liquid. The sensor arrangement  56  can include sensors that are both wet-stored and dry-stored. By “wet-stored”, it is meant the sensor is covered with a solution (typically aqueous) in storage before use. By “dry-stored”, it is meant the sensor is not covered by a liquid solution in storage before use. A “dry-stored” sensor can also include a sensor that is not covered by a liquid solution in storage before use and that is stored in a humid environment (i.e., there is vapor in contact with the dry-stored sensor). The particular example shown in FIG. 3 includes sensor arrangement  56  having each of these various types. The sensors in the sensor arrangement  56  are arranged relative to the first port  66 , second port  70 , and third port  78  based upon the type of sensor and/or whether it is wet-stored or dry-stored. This arrangement is discussed further below.  
     [0042] In the example shown in FIG. 3, the first fluid reservoir  68  contains calibration fluid therein. The calibration fluid is a fluid selected appropriate for the types of sensors in the sensor arrangement  56 . Typical calibration fluid useable will be an aqueous solution with the appropriate amount of test materials. That is, for each of the sensors in the sensor arrangement  56 , there will be a material in the calibration fluid to allow for a test measurement. During calibration, the calibration material flows into the fluid channel  54  and contacts the sensor arrangement  56 . Selected ones of the sensors in the sensor arrangement  56  are then calibrated based upon the known quantity of material in the calibration fluid.  
     [0043] In the cartridge  26  depicted, the second fluid reservoir  72  (FIG. 4) contains the fluid sample for analysis. For example, this fluid sample is body fluid, such as blood. In alternate embodiments, the second fluid reservoir  72  may be put in fluid communication with the first port  66 , interchangeably with the first fluid reservoir  68 . In this alternate embodiment, the second port  70  may be omitted from the cartridge  26 . This alternate embodiment would accommodate both dry-stored sensors and sensors calibrated with calibration fluid from the first fluid reservoir  68 .  
     [0044] In typical operation, calibration fluid is first dispensed from the first fluid reservoir  68 . From the first fluid reservoir  68 , the calibration fluid flows through the first port  66 , into the fluid channel  54 , over the sensor arrangement  56 , and then into the waste chamber  82 . In the example shown, the calibration fluid is not allowed to flow from the first port  66  in a direction toward the second port  70 . This is due to back pressures created during the manufacturing process (i.e., an air pocket between the first port  66  and second port  70 ). Also, during typical operation, the fluid sample, for example blood, is dispensed from the second fluid reservoir  72  and flows through the second port  70  into the fluid channel  54 , over the sensor arrangement  56  and then into the waste chamber  82 . The fluid sample, in this example, is not allowed to flow from the second port  70  through the first port  66  due to a blocking arrangement. One example blocking arrangement is described further below, in Section D.  
     [0045] The fluid channel  54 , in the one depicted in FIG. 3, has three sections. The first section  84  is downstream of the second port  70  and upstream of the first port  66 . The first section is generally between the second port  70  and the first port  66 . The first section  84  is for housing sensors that do not utilize fluid from the first fluid reservoir  68 . The first section  84  is also for accommodating sensors that use dry storage.  
     [0046] A second section  86  of the fluid channel  54  is between the second port  70  and the third port  78 . Preferably, the second section  86  is downstream of the first port  66  and the second port  70  and upstream from the third port  78 . The second section  86  accommodates sensors that utilize the calibration fluid from the first fluid reservoir  68  and that can be dry-stored.  
     [0047] A third section  88  of the fluid channel  54  accommodates sensors that may utilize the fluid from the fluid reservoir  68  and that can be wet-stored. The third section  88  is located between the third port  78  and the waste chamber  82 . In the example shown, the third section  88  is located downstream of each of the first port  66 , second port  70  and third port  78 .  
     [0048] In the embodiment depicted in FIG. 3, the first section  84  of the fluid channel  54  contains an oxygen sensor  90 . The oxygen sensor  90  senses the amount of oxygen in the body fluid sample from the second reservoir  72 . The oxygen sensor  90 , in the one shown, is preferably calibrated by exposure to the ambient air. In particular, the analyzer device  24  contains a barometer that is used to sense the air pressure in the fluid sample, from which is derived the partial pressure and the amount of oxygen content in the fluid sample. The oxygen sensor  90  is located downstream of the second port  70  such that, when appropriate, the fluid sample (e.g., blood or other body fluid) from the second fluid reservoir  72  is allowed to flow over the oxygen sensor  90  in order to take the measurement. The oxygen sensor  90  is located upstream of the first fluid port  66  such that when calibration fluid is dispensed from the first fluid reservoir  68  through the first port  66 , the oxygen sensor  90  is allowed to remain liquid-free and dry, and exposed to the air. During manufacturing in some applications, an air pocket is created in the first section  84 . In this example, the air pocket in first section  84  prevents the calibration fluid from flowing upstream in a direction from the first fluid port  66  to the second fluid port  70 .  
     [0049] Note that in alternate systems, the oxygen sensor  90  may also be calibrated with a perfluorocarbon non-aqueous calibration phase. This is disclosed in commonly assigned U.S. Pat. No. 5,231,030, incorporated herein by reference.  
     [0050] The first section  84  may also include a coagulation sensor. A typical, useable coagulation sensor will be dry-stored. In many applications, calibration of the coagulation sensor is optional.  
     [0051] The second section  86 , as described above, is for accommodating sensors that can be dry-stored, but also can use the fluid from the first fluid reservoir  68 . While a number of different sensors meet this criteria, in the example shown in FIG. 3, the second section  86  accommodates a creatinine sensor  92 , and a blood urea nitrogen (BUN) sensor  94 . In general, the sensors in the second section  86  may be enzymatic sensors. In this example, the creatinine sensor  92  and the BUN sensor  94  are arranged for dry storage. The sensors  92 ,  94  are downstream of the second fluid port  72 , so that when the sample is dispensed from the second fluid reservoir  72 , it flows over the sensors  92  and  94 . The sensors  92  and  94  are also downstream of the first fluid reservoir  68 , to allow for the flow of fluid thereover, when the fluid is dispensed from the first fluid reservoir  68 . The sensors  92 ,  94  are upstream of the third port  78 , which allows them to be dry-stored. An air pocket is formed with the first section  84  and second section  86  of the fluid channel  54  during the manufacturing process when the storage fluid is dispensed over the third section  88 .  
     [0052] The third section  88  of the fluid channel  54  contains sensors in the sensor arrangement  56  that are wet-stored and that can utilize the fluid from the fluid reservoir  68 . As such, the sensors in the third section  88  are downstream of each of the first port  66 , second port  70 , and third port  78 . The sensors in the third section  88  can include many different types of sensors including, for example, ion selective electrode sensors, conductometric sensors, and, in some instances, enzymatic sensors. Different types of sensor arrangements can be used within the third section  88 , and in the particular example shown, the sensor arrangement  56  in the third section  88  includes, in order from upstream to downstream, starting with the position just downstream of the third port  78 : a sodium sensor  96 , a chloride sensor  98 , a potassium sensor  100 , a calcium sensor  102 , a lactate sensor  104 , a pH sensor  106 , a carbon dioxide sensor  108 , a hematocrit sensor  110 , and a glucose sensor  112 .  
     [0053] In typical applications, the selected ones of the sensors in the third section  88  will be wet-stored. A septum  114  in fluid communication with the duct  80  allows for the introduction of storage fluid therewithin in order to flow through the duct  80  and into the third section  88  of the fluid channel  54 . One useable type of septum  114  will be a self-sealing gasket  115 , receptive to penetration by a needle on a syringe containing storage fluid. The storage fluid is typically hydration fluid that is similar to the calibration fluid contained within the first fluid reservoir  68 . One difference between the hydration fluid utilized to store the sensors in the third section  88  and the calibration fluid is that the hydration fluid does not contain the material for the enzymatic sensors. The hydration fluid is typically an aqueous solution with electrolytes, and in some implementations, may include an agent for promoting viscosity. The hydration fluid passes through the septum  114 , through the duct  80 , through the third port  78 , and over selected the sensors in the third section  88 , but not over the sensors in the first section  84  and second section  86 . An air pocket created during manufacturing in the first section  84  and second section  86  prevents flow of the hydration fluid over the sensors in the first section  84  and second section  86 . Typically, there may be some hydration fluid that drains into the waste chamber  82 , but the dimension of the channel  54  will keep at least some hydration fluid therewithin and covering the sensors in the third section  88 . The self-sealing gasket  115  of the septum  114  typically will prevent fluid from flowing from the fluid channel  54  back through the third port  78  and through the duct  80 .  
     [0054] In one type of application, each of the sensors sodium  96 , chloride  98 , potassium  100 , calcium  102 , lactate  104 , pH  106 , and carbon dioxide  108  are ion selective electrode type of sensors. In one example, the sensor hematocrit  110  is a conductometric type of sensor. The glucose sensor  112  is, in one example, an enzymatic sensor. The oxygen sensor  90 , in one example, is preferably an amperometric sensor, while the creatinine sensor  92  and BUN sensor  94  are, in selected implementations, enzymatic sensors.  
     D. Example Control System, FIGS.  5 - 7   
     [0055]FIG. 5- 7  illustrate, schematically, the fluid channel  54  and a system  120  controlling the direction of fluid flow within the channel  54 . In certain applications, it is desirable to use the system  120  to prevent the material flowing through the second port  70  from mixing with the fluid in the first fluid reservoir  68  that flows through the first port  66 . For example, in the embodiment illustrated in FIGS. 3 and 4, the system  120  prevents the fluid sample under analysis (for example blood) from mixing with the calibration fluid contained within the first fluid reservoir  68 . Such a mixture would contaminate the blood sample with the calibration fluid, and the resulting analysis on the blood sample would be inaccurate. One way of preventing this mixing is to block flow of the fluid sample from the fluid channel  54  into and through the first port  66 .  
     [0056] While a number of different ways of implementing this result can be achieved, in the particular example shown in FIG. 5, a valve arrangement  122  is shown. The valve arrangement  122  includes, at least, a first valve  124 . The first valve  124  is oriented to selectively block the first port  66  and allow for fluid to flow from the first fluid reservoir  68  through the first fluid port  66  and into the channel  54 . The first valve  124  also prevents flow from going backwards; that is, the first valve  124  blocks or prevents fluid from flowing from within the fluid channel  54  back through the first port  66  in a direction toward the first fluid reservoir  68 .  
     [0057] In the example shown in FIG. 5, the first valve  124  is a check valve  126 . The check valve  126  is shown in FIG. 5 to be in a closed position. The check valve  126  blocks flow from the fluid sample and the second port  70  from flowing in through the first port  66  and mixing with calibration fluid. Preferably, there is an air pocket formed in the first section  84  that prevents calibration fluid from flowing in a direction from the first fluid port  66  toward the second port  70 .  
     [0058] In some preferred systems, the valve arrangement  122  may also include an optional second valve  130 . The second valve  130  selectively controls fluid flow through the second port  70 . The second valve  130  preferably prevents fluid flow from the first fluid reservoir  68  and from the fluid channel  54  to flow through the second port  70  and toward the second fluid reservoir  72 . The second valve  130  is optional because, in use, the air pocket created within the first section  84  of the fluid channel  54  should prevent any flow of the calibration fluid from the first fluid reservoir in a direction through the first second  84  toward the second port  70 . For cautionary purposes, however, the second valve  130  can be included to insure that the fluid sample in the second fluid reservoir  72  does not mix with the calibration fluid in the first fluid reservoir  68 . In the example shown in FIG. 5, the second valve  130  is a check valve  132 . The check valve  132  prevents any fluid within the channel  54  from flowing backwards from the channel  54  through the second port  70  and toward the second fluid reservoir  72 . In FIG. 5, the second check valve  132  is shown in a closed position.  
     [0059] Attention is next directed to FIGS. 6 and 7. In FIG. 6, the first check valve  126  is shown in an open position, while the second check valve  130  is shown in a closed position. FIG. 6 would be the position of the valve arrangement  122  when the calibration fluid is being dispensed from the first fluid reservoir  68 , through the first port  66 , and into the fluid channel  54 . The air pocket in first section  84  and the closed position of the second check valve  132  prevents flow of the calibration fluid toward the second port  70 . Instead, the calibration fluid flows across the second section  86  and third section  88  in a direction toward the waste chamber  82  (FIGS. 3 and 4).  
     [0060]FIG. 7 shows the first valve  124  closed and the second valve  130  open. This would be the position of the valve arrangement  122  when the fluid sample is deployed from the second fluid reservoir  72  and across all of the sensors in the sensor arrangement  56 . The check valve  132  is open, which allows the fluid sample (e.g., body fluid including blood) to flow from the second fluid reservoir  72  downstream across the first section  84 , second section  86 , and third section  88  and finally into the waste chamber  82 . The check valve  126  is closed to prevent the fluid sample from mixing with the calibration fluid, and to prevent the fluid sample from flowing into the first port  66  toward the first fluid reservoir  68 .  
     [0061]FIG. 5 shows both of the first valve  124  and second valve  130  in closed positions. This is the position of the valve arrangement  122  when the cartridge  26  is in storage and is awaiting use.  
     [0062] The check valves  126 ,  132  can be constructed in a variety of implementations. Examples include rubber flaps, or with the check valve  132 , a piece of adhesive tape.  
     E. Calibration Dispensing Arrangement, FIGS.  8 - 14   
     [0063]FIGS. 8 and 9 show a schematic, cross-sectional view of one embodiment of the first fluid reservoir  68 . The first fluid reservoir  68  preferably includes a fluid dispensing arrangement  140 . The fluid dispensing arrangement  140  allows for convenient and quick dispensing of fluid contained within the fluid reservoir  68  through a fluid passage  142  and in through the first port  66  (FIGS. 3 and 4).  
     [0064] The fluid dispensing arrangement  140  preferably includes an actuator  144  constructed and arranged to initiate fluid flow from the internal volume  146  of the first fluid reservoir  68  and through the fluid passage  142 , and ultimately through the first port  66  in the cartridge  26 . In the one shown, the actuator  144  is embodied as a push-button  148 . The preferred push-button  148  is flexible such that it is over-center engageable. By the term “over-center engageable”, it is meant that once the push-button  148  is pushed a certain distance inward toward a remaining portion of the first fluid reservoir  68 , it remains under tension in its actuated position. This is explained further below. In the preferred embodiment illustrated, the over-center engageable button  148  is included as part of a lid  150  that is mountable over a base housing  152 . One example of an “over-center engageable” button is a button on the plastic lid of a soft-drink container that can be selectively pushed to indicate the type of beverage contained therein (e.g. “diet”, “tea”, etc.)  
     [0065] FIGS.  10 - 12  show the base housing  152  in further detail. The base housing  152  includes an outer wall  154  defining a mouth  156 . The mouth  156  is for receiving the lid  150 . The wall  154  circumscribes the internal volume  146 . The base housing  152  further includes a duct  158 , defining the fluid passage  142 . Calibration fluid flows from the internal volume  146  through the fluid passage  142  in the duct  158 , upon initiation by the push-button  148 . The base housing  152  further includes support member  160  to help properly orient and mount the first fluid reservoir  68  onto and relative to the cartridge  26 . As can be seen in FIG. 11, in preferred embodiments, the support  160  can be cross-shaped for distributing the force. The base housing  152 , in the particular one shown, further includes a handle  162  extending from the wall  154 . The handle  162  helps to manipulate the first fluid reservoir  66  relative to the cartridge  26 .  
     [0066]FIGS. 13 and 14 illustrate the lid  150  in further detail. As mentioned above, in preferred embodiments, the lid  150  includes the over-center engageable push-button  148 . Preferably, the lid  150  is constructed of thin material, i.e. less than 0.02 inch thick, for example about 0.005-0.015 inch thick. Certain preferred embodiments are about 0.008-0.011 inch thick. Useable materials include, for example, natural high impact polystyrene.  
     [0067] Still in reference to FIGS. 13 and 14, the push-button  148  includes a dome-shaped portion  164  that is depressible in a direction toward the base housing  152 , when the lid  150  is operably oriented on the base housing  152 .  
     [0068] Attention is again directed to FIGS. 8 and 9. FIG. 8 shows the button  148  in a non-engaged position. FIG. 9 shows the button  148  in an engaged position. The dome-shaped portion  164 , in FIG. 8, before actuation and before depressing, is oriented outward in a direction away from the base housing  152  (i.e., is convex relative to the base housing  152 ). In FIG. 9, the dome-portion is oriented in a direction toward the base housing  152  (i.e., is concave relative to the base housing  152 ). By depressing the button  148  when it is in the position shown in FIG. 8, the lid  158  flexes over-center such that the dome-portion  164  moves from the position in FIG. 8 oriented away from the base housing  152  to a position oriented toward the base housing  152  in FIG. 9.  
     [0069] Movement of the push-button  148  from the convex position of FIG. 8 to the concave position in FIG. 9 decreases the volume  146  containing the calibration fluid. This decrease in volume initiates flow and forces flow of the calibration fluid through the fluid passage  142  in the duct  158 . When the first fluid reservoir  68  is operably mounted on the cartridge  26 , this flow of calibration fluid from the fluid passage  142  then flows through the first fluid port  66  and into the fluid channel  54 .  
     F. Methods  
     [0070] In operation, to use the cartridge  26 , the cartridge  26  is operably inserted or plugged into the analyzer device  24 . The analyzer device  24  can include, for example, an IMRA blood analyzer as described above; or the analyzer device  24  can include a PORTAL blood analyzer as described above which is pluggable into monitor  28 ; or, the analyzer device  24  can include the device as described in U.S. Pat. No. 6,066,243 incorporated herein by reference. The body fluid, for example blood, can be withdrawn from the patient  22  in the syringe  74  and secured to the cartridge  26  at luer lock  76 . This can be done either before inserting the cartridge  26  into the analyzer device  24  or afterwards, and before or after calibration.  
     [0071] When using the analyzer  31 , the cartridge  26  is inserted or plugged into the analyzer  31  by sliding it into the cartridge receiving area  32  and making electrical contact between the conductor arrangement  58  and electrical contacts on the analyzer  31 .  
     [0072] Selected ones of the sensors in the sensor arrangement  56  are then calibrated. To calibrate selected ones of the sensors in the sensor arrangement  56 , the calibration fluid is dispensed from the first fluid reservoir  68  and into the fluid channel  54 . To do this, the actuator  144  is engaged. To engage the actuator  144 , the user pushes her finger against the push-button  148  and depresses the push-button  148  until the dome portion  164  flips from a position of being convex relative to the base housing  152  (FIG. 8) to a position of being concave relative to the base housing  152  (FIG. 9). That is, the push-button  148  moves over-center from its position in FIG. 8 to its position in FIG. 9. This causes the calibration fluid in the volume  146  to pass through the fluid passage  142  and through the first port  66 . The force of the fluid causes the check valve  126  to move from a closed position (FIG. 5) to an open position (FIG. 6). The air pocket and back pressure in the first section  84  downstream of the second port  70  and upstream of the first port  66  prevents the calibration fluid from flowing in a direction from the first port  66  to the second port  70 . The calibration fluid flows into the fluid channel  54  through the second section  86  and downstream through the third section  88 .  
     [0073] The analyzer  31  includes the proper electronics to perform the calibration of selected ones of the sensors, including the sensors located in the first section  84 . As mentioned above, the sensors in the first section  84  are not covered with calibration fluid from the first fluid reservoir  68 . Selected ones of the sensors in the first section  84  may be calibrated by other means. For example, the oxygen sensor  90  is calibrated by exposure to the ambient air and through a barometer in the analyzer  31 .  
     [0074] It should be noted that after deployment or dispensing of the calibration fluid from the first fluid reservoir  68 , the push-button  148  stays in its depressed position of FIG. 9. This is useful in not creating a vacuum to draw the calibration fluid back up through the first port  66  and through the fluid passage  142 . The fixed position of the push-button  148  in its depressed position does not allow for backflow of the calibration fluid.  
     [0075] Next, the fluid sample, in this example blood, is dispensed. The fluid sample may be dispensed from the second fluid reservoir  72  into the fluid channel  54  in order to accomplish the step of analyzing the fluid sample. This is done by, first, if the syringe  74  has not yet been mounted onto the cartridge  26 , mounting the syringe  74  to the cartridge  26 . Next, pushing the blood from the syringe  74  through the second port  70  and into the fluid channel  54 , while preventing the blood from mixing with the calibration fluid when the fluid sample is in the fluid channel  54 . To prevent the blood from mixing with the calibration fluid, when the blood is pushed from the syringe  74  in through the second port  70 , the blood pushes the air pocket located in first section  84  through the fluid channel  54 . Movement of the blood into the fluid channel  54  causes the check valve  126  to move from an open position (FIG. 6) into a closed position (FIG. 7). The check valve  132  oriented within the second portion  70  is opened by movement of the blood from the syringe  74  through the second port  70 . The closing of the first valve  126  blocks flow of the blood from the fluid channel  54  into and through the first port  66 . This prevents the blood and the calibration fluid from mixing. As the blood is forced into the channel  54 , the air pocket in first section  84  moves downstream through the second section  86  and third section  88 . This also urges the calibration fluid from the fluid channel  54  and into the waste chamber  82 . As this happens, the blood is then allowed to cover all of the sensors in the sensor arrangement  56 . The analyzer  31  then evaluates the characteristics of the blood through the sensor arrangement  56 . The results are then displayed on the display  40 , or integrated by way of monitor  28  into patient database  30 . The calibration fluid is prevented from flowing from the fluid channel  54  through the second port  70 . This is due to the check valve  132 , as well as the check valve  126 .  
     [0076] In some implementations, the fluid sample may be dispensed through the first port  66  by interchanging the first reservoir  68  and the second reservoir  72 .  
     [0077] In some implementations, the step of calibration may take place after the step of dispensing the fluid sample and analyzing.  
     [0078] After the fluid sample has been analyzed, and the results provided, the caregiver can make the appropriate diagnosis and prescribe appropriate treatment to the patient  22 . This entire procedure, from drawing the blood sample to receiving the results is all done in under 20 minutes, usually less than 15 minutes, and typically less than 10 minutes. As can be appreciated, this provides quick, point-of-care diagnostic information.  
     [0079] After the results are received, the cartridge  26  is removable from the analyzer  31 . The cartridge  26  may be disposed of, if appropriate, or re-used, if appropriate.  
     G. Example Cartridge  
     [0080] One typical cartridge  26  constructed using principles of this disclosure has a weight of less than 5 lbs, typically less than 1 lb. It has a perimeter area of not greater than 10 in 2 , and often, not greater than 5 in 2 . It is sized to be “handheld”; that is, it is sized to be manipulated by a human hand.  
     [0081] It typically will hold 100-400 micro liters of calibrant fluid. It typically holds a fluid sample of 85 micro liters to 3 milliliters, and often uses no more than 100 micro liters. The fluid channel containing the sensors will often contain no more than 50 micro liters of the fluid sample.