Patent Publication Number: US-8980635-B2

Title: Disposable cartridge for fluid analysis

Description:
This application is a continuation of U.S. patent application Ser. No. 13/337,916, filed Dec. 27, 2011, now U.S. Pat. No. 8,663,583, and entitled “DISPOSABLE CARTRIDGE FOR FLUID ANALYSIS” which incorporated herein by reference in their entirety. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates generally to disposable fluidic cartridges for analysis of a fluid, and more particularly to disposable fluidic cartridges for analysis of blood and/or other biological fluids. 
     BACKGROUND 
     Chemical and/or biological analysis is important for life sciences research, clinical diagnostics, and a wide range of environmental and process monitoring. In some cases, sample analyzers are used to perform and/or assist in performing chemical and/or biological analysis of a sample fluid. The sample fluid may be a liquid or a gas, depending on the application. 
     Many sample analyzers are rather large devices that are used in a laboratory environment by trained personnel. To use many sample analyzers, a collected sample must first be processed, such as by diluting the sample to a desired level, adding appropriate reagents, centrifuging the sample to provide a desired separation, and so on, prior to providing the prepared sample to the sample analyzer. To achieve an accurate result, such sample processing must typically be performed by trained personnel, which can increase the cost and time required to perform the sample analysis. 
     Many sample analyzers also require operator intervention during the analysis phase, such as requiring additional information input or additional processing of the sample. This can further increase the cost and time required to perform a desired sample analysis. Also, many sample analyzers merely provide raw analysis data as an output, and further calculations and/or interpretation must often be performed by trained personnel to make an appropriate clinical or other decision. 
     SUMMARY 
     The present disclosure relates generally to disposable fluidic cartridges for analysis of a fluid, and more particularly to disposable fluidic cartridges for analysis of blood and/or other biological fluids. In one illustrative embodiment, a disposable blood analysis cartridge may include a sample introduction port; a sample collection reservoir for receiving a blood sample from the sample introduction port; an absorbance measurement channel including a cuvette, with a first gas permeable membrane located downstream of the cuvette; an optical scattering measurement channel including a hydrodynamic focusing region, with a second gas permeable membrane located upstream of the hydrodynamic focusing region; one or more valves disposed between the sample collection reservoir, and the absorbance measurement channel and the optical scattering measurement channel; and one or more vacuum ports in fluid communication with the absorbance measurement channel through the first gas permeable membrane, and in fluid communication with the optical scattering measurement channel through the second gas permeable membrane. When a negative pressure is applied to the one or more vacuum ports, at least part of the blood sample is drawn from the sample collection reservoir, through the one or more valves and at least partially into the absorbance measurement channel and the optical scattering measurement channel. 
     In some illustrative embodiments, a disposable blood analysis cartridge may include: a sample introduction port; a sample collection reservoir for receiving a blood sample from the sample introduction port; an absorbance measurement channel including a cuvette, with a first gas permeable membrane located downstream of the cuvette; an optical scattering measurement channel including a hydrodynamic focusing region, with a second gas permeable membrane located upstream of the hydrodynamic focusing region; one or more valves disposed between the sample collection reservoir, and the absorbance measurement channel and the optical scattering measurement channel; one or more vacuum ports in fluid communication with the absorbance measurement channel through the first gas permeable membrane, and in fluid communication with the optical scattering measurement channel through the second gas permeable membrane; a reagent introduction port in fluid communication with the optical scattering measurement channel; and a sheath fluid introduction port in fluid communication with the optical scattering measurement channel. When a negative pressure is applied to the one or more vacuum ports, at least part of the blood sample is drawn from the sample collection reservoir, through the one or more valves and at least partially into the absorbance measurement channel and the optical scattering measurement channel. 
     In yet other illustrative embodiments, a method of analyzing a blood sample in a cartridge may include receiving a blood sample via a blood sample introduction port of the cartridge, the blood sample being drawn into a sample collection reservoir by capillary action; applying a negative pressure to one or more vacuum ports of the cartridge, the negative pressure causing the blood sample to be drawn from the sample collection reservoir, through one or more open valves, and into a cuvette of an absorbance measurement channel and into at least part of an optical scattering measurement channel having a hydrodynamic focusing region; and closing the one or more valves. In some cases, the method may include receiving a reagent via a reagent introduction port, the reagent mixing with the blood sample in the optical scattering measurement channel upstream of the hydrodynamic focusing region; receiving a sheath fluid via a sheath fluid introduction port, the sheath fluid being injected at or near the hydrodynamic focusing region of the optical scattering measurement channel; performing an optical scatter measurement using a window that is adjacent the hydrodynamic focusing region of the optical scattering measurement channel; and performing an absorbance measurement using the cuvette of the absorbance measurement channel. 
     The preceding summary is provided to facilitate an understanding of some of the innovative features unique to the present disclosure and is not intended to be a full description. A full appreciation of the disclosure can be gained by taking the entire specification, claims, drawings, and abstract as a whole. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure may be more completely understood in consideration of the following description of various embodiments in connection with the accompanying drawings, in which: 
         FIG. 1  is a perspective view of an illustrative sample analyzer and cartridge; 
         FIG. 2  is a front schematic view of an illustrative fluid analysis cartridge that may be received by a sample analyzer, such as the sample analyzer of  FIG. 1 ; 
         FIG. 3  is a front schematic view of an illustrative fluid analysis cartridge that may be received by a sample analyzer, such as the sample analyzer of  FIG. 1 ; 
         FIG. 4  is a front schematic view of an illustrative fluid analysis cartridge that may be received by a sample analyzer, such as the sample analyzer of  FIG. 1 ; 
         FIGS. 5A and 5B  are partial side cross-sectional views of the illustrative cartridge shown in  FIG. 4 , taken along line  5 - 5 ; 
         FIG. 6  is a front schematic view of an illustrative fluid analysis cartridge that may be received by a sample analyzer, such as the sample analyzer of  FIG. 1 ; 
         FIG. 7  is a partial cross-section view of a portion of the fluid analysis cartridge of  FIG. 6 ; 
         FIG. 8  is a front schematic view of an illustrative fluid analysis cartridge that may be received by a sample analyzer, such as the sample analyzer of  FIG. 1 ; 
         FIG. 9  is an exploded view of the illustrative fluid analysis cartridge of  FIG. 8 ; and 
         FIG. 10  is front schematic view of an illustrative fluid analysis cartridge that may be received by a sample analyzer, such as the sample analyzer of  FIG. 1 . 
     
    
    
     While the disclosure is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit aspects of the disclosure to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the disclosure. 
     DESCRIPTION 
     The following description should be read with reference to the drawings wherein like reference numerals indicate like elements throughout the several views. The detailed description and drawings show several embodiments which are meant to illustrative of the claimed disclosure. 
     The present disclosure relates generally to disposable fluidic cartridges for analysis of a fluid and more particularly, to disposable fluidic cartridges for analysis of a variety of biological fluids including, but not limited to, blood, blood products (e.g. controls, linears, calibrators, etc.), urine, and/or other biological fluids from mammalian and non-mammalians sources. In some cases, the present disclosure may provide sample analyzers that are simple to operate and have a reduced risk of providing erroneous results. In some examples, the sample analyzer may be, for example, a blood analyzer such as a flow cytometer, a hematology analyzer, a clinical chemistry analyzer (e.g., glucose analyzer, ion analyzer, electrolytes analyzer, dissolved gasses analyzer, and so forth), a urine analyzer or any other suitable analyzer, as desired. 
       FIG. 1  is a perspective view of an illustrative sample analyzer  12  and analysis cartridge  14 . In some cases, the sample analyzer  12  is adapted to be used at the point of care of a patient, such as in a doctor&#39;s office, in the home, or elsewhere in the field. The ability to provide a sample analyzer  12  that can be reliably used outside of the laboratory environment, with little or no specialized training, may help streamline the sample analysis process, reduce the cost and burden on medical personnel, and increase the convenience of sample analysis for many patients, including those that require relatively frequent blood monitoring/analysis. While the sample analyzer  12 , as depicted in the illustrative example provide in  FIG. 1 , may include a flow cytometer, it will be understood that the sample analyzer  12  may include any suitable type of sample analyzer, as desired. 
     In the illustrative example of  FIG. 1 , sample analyzer  12  may include a housing  16  having a base  18 , a cover  20 , and a hinge  22  that attaches the base  18  to the cover  20 . Depending on the types of analyses being performed, the base  18  may include one or more light sources. For example, in some embodiments, the base  18  may include a first light source  24   a  for optical light scattering measurements and a second light source  24   b  for optical absorption measurements. In some case, depending upon the application, the base  18  may include additional light sources for additional measurements. In addition, the base  18  may include associated optics and the necessary electronics for operation of the sample analyzer including the light sources  24   a  and  24   b . Each of the light sources  24   a  and  24   b  may be a single light source or a multiple light source, depending on the application. The illustrative cover  20  may include a pressure source (e.g., pressure-chambers with control microvalves) and one or more light detectors for detecting light emitted from the one or more light sources. In some cases, the cover  20  may include a first light detector  26   a  and a second light detector  26   b , each with associated optics and electronics. Each of the light detectors  26   a  and  26   b  may also be a single light detector or multiple light detectors, depending on the application. Polarizers and/or filters may also be provided, if desired, depending on the application. 
     It is contemplated that the disposable blood analysis cartridge  14  may include a microfluidic circuit. The microfluidic circuit may be suitable for processing (e.g. lyse, sphere, dilute, mix, etc.) a sample, and deliver the sample to an appropriate region of the cartridge  14  for analysis. In some embodiments, the microfluidic circuit may include an optical scattering measurement channel, an optical absorbance measurement channel, or both. 
     In some cases, the cartridge  14  may be formed from a laminated structure having multiple layers, with some layers including one or more channels passing through the layer. However, it is contemplated that the removable cartridge  14  may be constructed in any suitable manner including by injection molding, or any other suitable manufacturing process or approach, as desired. 
     In some cases, the disposable cartridge  14  may include holes  28   a  and  28   b  for receiving registration pins  30   a  and  30   b  in the base  18 . This may help provide alignment and coupling between the different parts of the instrument, if desired. The removable cartridge  14  may also include a first transparent window  32   a  and a second transparent window  32   b , which are in alignment with the first and second light sources  24   a  and  24   b  and the first and second detectors  26   a  and  26   b , respectively. The cartridge  14  may also include a sample introduction port  36  for introduction of a fluid sample such as, for example, a whole blood sample into the cartridge  14 . The whole blood sample may be obtained via a finger stick or a blood draw. 
     During use, and after a fluid sample has been delivered into the disposable cartridge  14  via the sample introduction port  36 , the disposable cartridge  14  may be inserted into the housing  16 . In some cases, the removable cartridge  14  may be inserted into the housing  16  when the cover  20  is in the open position. However, in other examples, the removable cartridge  14  may be inserted into the housing in any suitable way. For example, the housing may have a slot, and the disposable cartridge  14  may be inserted into the slot of the housing  16 . 
     When the cover  20  is closed, the system may be pressurized. Once pressurized, the sample analyzer  12  may perform a blood analysis on the collected blood sample. In some cases, the blood analysis may include a complete blood count (CBC) analysis, but other types of analysis can be performed, depending on the application. In some cases, for example, the blood analysis may include, a red blood cell count (RBC), a platelet count (Plt), a mean cell hemoglobin concentration (MCHC), a mean cell volume (MCV), a relative distribution width (RDW), hemocrit (Hct) and/or a hemoglobin concentration (Hb). In some cases, the blood analysis on the collected blood sample may also a white blood cell count (WBC), three or five part white cell differentiation, total white blood cell count and/or on-axis white blood cell volume. After analysis is complete, the cartridge  14  may be disposed of in an appropriate waste receptacle. 
       FIG. 2  is a front schematic view of an illustrative fluid analysis cartridge  50  that may be received by a sample analyzer, such as the sample analyzer  12  discussed above. In some cases, the blood analysis cartridge  50  may be a disposable blood analysis cartridge. The cartridge  50  may be configured such that once a blood sample is received in the cartridge  50 ; the cartridge  50  may be self-contained such that special handling measures are not required. However, as with many biological samples, it would be recommend that ordinary precautionary measures be taken if desired. 
     In some cases, and as shown in the illustrative example of  FIG. 2 , the cartridge  50  may be configured for both optical light scattering measurements and optical absorbance measurements, and may be configured such that a pusher fluid, one or more reagents, and a sheath fluid, which may be necessary to move the sample through the different regions of the cartridge and process the sample for analysis, may be delivered by the sample analyzer  12 . 
     In some cases, and as shown in  FIG. 2 , the cartridge  50  may include at least one sample introduction port  54  for introduction of a sample into the cartridge  50 . In some cases, the cartridge  50  may also include a second sample introduction port  58 , but this is not required. For example, in some cases, the cartridge  50  may include a single sample introduction port, coupled to a bifurcated sample delivery channel, wherein the bifurcated sample delivery channel is in fluid communication with two or more measurement regions of the cartridge  50 . In many cases, the first and second sample introduction ports  54  and  58  may include an anti-coagulant coating provided on an inner surface thereof to facilitate sample loading. In other cases, the first and second sample introduction ports  54  and  58  may include a hydrophilic coating which may facilitate loading of the sample via capillary action. However, this is not required. In some cases, the sample introduction port may be configured to mate with and/or receive a syringe for delivery of a fluid sample into the cartridge  50 , but again, this is not required. Any suitable fluid connection may be used. 
     As illustrated in the example shown in  FIG. 2 , the first sample introduction port  54  may be in fluid communication with a first measurement region  62  of the cartridge  50 , and the second sample port  58  may be in fluid communication with a second measurement region  66  of the cartridge  50 . In some cases, the first measurement region  62  is an optical light scattering measurement region  62  that may include a first sample loading channel  70 , a reagent channel  76 , and an optical light scattering measurement channel  82 . In addition, the second measurement region  66  may be an optical absorbance measurement region  66 , and may include a second sample loading channel  88  and an optical absorbance measurement channel  94 . 
     Once a sample is loaded into the first sample loading channel  70 , a pusher fluid may be introduced via the first sample introduction port  54  to push the sample from the first sample loading channel  70  into the reagent channel  76  which is in fluid communication with the first sample loading channel  70 . In some cases, the reagent channel  76  may include a reagent introduction port  100  for introduction of one or more reagents into the reagent channel  76  for processing the sample. The number and/or type of reagents to be introduced into the reagent channel  76  may depend upon the application. For example, the reagents may include a lysing reagent, a sphering reagent, a diluent, etc. The reagent introduced through the reagent introduction port  100  may contact and mix with the sample entering the reagent channel  76  from the first sample loading channel  70 . In some embodiments, the reagent channel  76  may include a number of bends or turns  106  that may increase the length of the reagent channel  76 , which may increase the length of time the sample spends in the reagent channel. In some cases, as shown, the bend or turn  106  may be a substantially U-shaped bend or turn  106 , and may help keep particles such as blood cells dispersed as the sample travels through the reagent channel  76 . The increase in dwell or residence time may provide a sufficient amount of time needed for the reagent to properly react with and process the sample for analysis. The processed sample may then delivered from the reagent channel  76  to the optical light scattering measurement channel  82  for analysis using an optical light scattering measurement technique such as, for example, flow cytometry. 
     The optical scattering measurement channel  82  may include a hydrodynamic focusing region  110  having a narrow channel region  112  over which a transparent window  116  may be disposed. In some cases, the processed sample may be delivered from the reagent channel  76  to the optical measurement channel  82  at a location upstream relative to the hydrodynamic focusing region  110 . In the example shown, sheath fluid may be introduced into the cartridge via a sheath fluid introduction port  114 . The sheath fluid may be provided at such a flow rate that it surrounds the processed sample and forms a “sheath” around the sample “core”. In some cases, the sheath fluid flow rate may be controlled such that it is higher than the processed sample flow rate to aid in core formation downstream within the hydrodynamic focusing region  110 . 
     In some cases, as shown in the example shown in  FIG. 2 , the sheath fluid introduction port  114  may be fluidly coupled to a bifurcated sheath fluid delivery channel  116  including a first elongated sheath fluid sub channel  118  and a second elongated sheath fluid sub channel  122 , but this is not required. The processed sample may be introduced into the first elongated sheath fluid channel  118  from the side at an intersecting region  126 . In some cases, as shown, the processed sample may be introduced into first elongated sheath fluid sub channel at an angle, α, of approximately 90 degrees, relative to the direction of flow of the sheath fluid. It is contemplated that the processed sample may be introduced into first elongated sheath fluid sub channel at an angle, α, of between 5 and 175 degrees, between 25 and 115 degrees, between 45 and 135 degrees, between 60 and 150 degrees, between 85 and 95 degrees, or any other suitable angle relative to the direction of flow of the sheath fluid. This can be the case where only a single sheath fluid delivery channel is provided (not shown in  FIG. 2 ), or a bifurcated sheath fluid delivery channel  116  is provided (as shown in  FIG. 2 ). 
     When provided, the second elongated sheath fluid sub channel  122  may intersect with the first elongated sheath fluid sub channel  118  at a second intersection region  128 , located downstream from the first intersection region  126 . In some cases, and as shown in  FIG. 2 , the second elongated sheath fluid sub channel  122  may deliver a portion of the sheath fluid from a position located above the first sheath fluid sub channel  118  such that the sheath fluid from the second sheath fluid sub channel  122  enters the first sheath fluid sub channel  118  from the top. In some cases, the second elongated sheath fluid sub channel  122  may deliver another portion of the sheath fluid from a position located below the first sheath fluid sub channel  118  such that the sheath fluid from the second sheath fluid sub channel  122  enters the first sheath fluid sub channel  118  from the bottom. The combination of the processed sample entering the first sheath fluid sub channel  118  from the side coupled with the delivery of a portion of the sheath fluid from an upper position and/or a lower position may facilitate better positioning of the core within the hydrodynamic focusing region  110 . In some cases, this configuration may provide three-dimensional hydrodynamic focusing of the processed sample within the sheath fluid flow, which may result in a more reliable and accurate measurement of sample properties in the optical light scattering measurement channel  82 . In the example shown, the sheath fluid carries the processed sample into the hydrodynamic focusing region  110  for hydrodynamic focusing of the processed sample and analysis by flow cytometry. The processed sample then passes from the optical scattering measurement channel  82  into a waste channel  132  where it is carried to a waste storage reservoir  136 . In some cases, the waste storage reservoir  136  may be a self-contained, on-card waste storage reservoir. 
     In some cases, and as discussed above, the cartridge  50  may include an optical absorbance measurement region  66 . In some cases, as shown, at least a portion of the optical absorbance measurement region  66 , such as the optical absorbance measurement channel  94 , may pass over and/or under the optical light scattering measurement region  62  including the optical scattering measurement channel  82 . For example, as shown in  FIG. 2 , the second sample loading channel  88  of the optical absorbance measurement region  66  passes over or under the reagent channel  76  of the optical light scattering measurement region  62 . 
     In the example shown, sample may be introduced into the second sample loading channel  88  via a second sample introduction portion  58 . In some cases, the sample may be a whole blood sample, but this is not required. Sample may flow from the second sample loading channel  88  into the optical absorbance measurement channel  94 . The optical absorbance measurement channel  94  includes a cuvette  142  through which light may be passed to obtain an optical absorbance measurement which may be used to determine one or more of the sample properties. Sample may be delivered from the second sample loading channel  88  to the optical measurement channel  94  until the cuvette  142  is substantially filled with sample. In some cases, the second sample loading channel  88  may include an indicator window  148  which may serve as a visual reference point for sample loading. For example, sample loading may be ceased when sample is visible within the indicator window  148 , indicating that the optical measurement channel  94  including the cuvette  142  has been substantially filled with sample and no further sample is needed. 
     In some embodiments, as shown, each of the optical light scattering measurement channel  82  and the optical absorbance measurement region  66  may be configured to deliver waste sample to a waste storage reservoir  136 . In some embodiments, the waste storage reservoir  136  may be configured to be aspirated by the sample analyzer such as, for example, sample analyzer  12 , but this not required. In other embodiments, the waste storage reservoir  136  may be configured such that it receives and collects the waste sample and contains the sample within the cartridge  50  such that the cartridge  50  containing the waste sample and any remaining unused sample and/or reagents can be disposed of after use. 
       FIG. 3  is a front schematic view of an illustrative fluid analysis cartridge  150  that may be received by a sample analyzer, such as the sample analyzer  12  of  FIG. 1 . In some cases, the blood analysis cartridge  150  is a disposable blood analysis cartridge. The cartridge  150  may be configured such that once a blood sample is received in the cartridge  150 ; the cartridge  150  becomes self-contained such that special handling measures are not required. However, as with many biological samples, it would be recommend that ordinary precautionary measures be taken if desired. 
     In some cases, as shown in the illustrative example of  FIG. 3 , the cartridge  150  may be configured for both optical light scattering measurements and optical absorbance measurements, and may be configured such that the necessary pusher fluid, one or more reagents, and a sheath fluid, which may be necessary to move the sample through the different regions of the cartridge and process the sample for analysis are delivered by the sample analyzer  12 . As shown in the illustrative example provided by  FIG. 3 , cartridge  150  may include an optical light scattering measurement region  156  and an optical absorbance measurement region  162 . 
     In some cases, as shown, the cartridge  150  may include at least one sample introduction port  154  for introduction of a sample into the cartridge  150 . Additionally, the cartridge  150  may include a second sample introduction port  158 , but this is not required. For example, in some cases, the cartridge  150  may include a single sample introduction port coupled to a bifurcated sample delivery channel, wherein the bifurcated sample delivery channel is in fluid communication with two or more measurement regions (e.g. the optical light scattering measurement region  156  and optical absorbance measurement region  162 ) of the cartridge  150 . In many cases, the first and second sample introduction ports  154  and  158  may include an anti-coagulant coating provided on an inner surface thereof to facilitate sample loading. In other cases, the first and second sample introduction ports  154  and  158  may include a hydrophilic coating which may facilitate loading of the sample via capillary action. However, this is not required. 
     As illustrated in the example shown in  FIG. 3 , the first sample introduction port  154  may be in fluid communication with the optical light scattering measurement region  156  via a first sample loading channel  170 . In addition, the second sample introduction port  158  may be in fluid communication with the optical absorbance measurement region  162  via second sample loading channel  174 . Once sample is loaded into the first sample loading channel  170 , a pusher fluid may be introduced via the first sample introduction port  154  to push the sample from the sample loading channel into a reagent channel  176 , which is in fluid communication with the first sample loading channel  170 . In some cases, the reagent channel  176  may include a reagent introduction port  180  for introduction of one or more reagents into the reagent channel  176  for processing the sample. The number and/or type of reagents to be introduced into the reagent channel may depend upon the application. For example, the reagents may include a lysing reagent, a sphering reagent, a diluent, etc. The reagent introduced through the reagent introduction port  180  may contact and mix with the sample entering the reagent channel  176  from the first sample loading channel  170 . In some embodiments, the reagent channel  176  may include a number of bends or turns  186  that increase the length of the reagent channel  176 , which may increase the length of time the sample spends in the reagent channel (sometimes referred to as dwell time). In some cases, as shown, the bend or turn  186  may be a substantially U-shaped bend or turn  186 , but this is not required. The increase in dwell or residence time may provide a sufficient amount of time needed for the reagent to properly react with and process the sample for analysis. The processed sample may be delivered from the reagent channel  176  to the optical light scattering measurement region  156  for analysis using an optical light scattering measurement technique such as, for example, flow cytometry. 
     The optical scattering measurement region  156  may include an optical light scattering measurement channel  182  having a hydrodynamic focusing region  190  including a narrow channel region over which a light transparent window  196  may be disposed. In some cases, the processed sample may be delivered from the reagent channel  176  to the optical measurement channel  182  at a location upstream relative to the hydrodynamic focusing region  190 . Sheath fluid may be introduced into the cartridge via a sheath fluid introduction port  198 . The sheath fluid may be provided at such a flow rate that it surrounds the processed sample and forms a “sheath” around the sample “core”. In some cases, the sheath fluid flow rate may be controlled such that it is higher than the processed sample flow rate to aid in core formation downstream within the hydrodynamic focusing region  190 . 
     In some cases, as shown in the example shown in  FIG. 3 , the sheath fluid introduction port  198  may be fluidly coupled to a bifurcated sheath fluid delivery channel  202  including a first elongated sheath fluid sub channel  208  and a second elongated sheath fluid sub channel  212 , but this is not required. The processed sample may be introduced into the first elongated sheath fluid channel  208  from the side at an intersecting region  216 . In some cases, as shown, the processed sample may be introduced into first elongated sheath fluid sub channel at an angle, α, of approximately 90 degrees, relative to the direction of flow of the sheath fluid. It is contemplated that the processed sample may be introduced into first elongated sheath fluid sub channel at an angle, α, of between 5 and 175 degrees, between 25 and 115 degrees, between 45 and 135 degrees, between 60 and 150 degrees, between 85 and 95 degrees, or any other suitable angle relative to the direction of flow of the sheath fluid. This can be the case where only a single sheath fluid delivery channel is provided (not shown in  FIG. 3 ), or a bifurcated sheath fluid delivery channel  202  is provided (as shown in  FIG. 3 ). 
     When provided, the second elongated sheath fluid sub channel  212  may intersect with the first elongated sheath fluid sub channel  208  at a second intersection region  218  located downstream from the first intersection region  216 . In some cases, and as shown in  FIG. 3 , the second elongated sheath fluid sub channel  212  may deliver a portion of the sheath fluid from a position located above the first sheath fluid sub channel  208  such that the sheath fluid from the second sheath fluid sub channel  212  enters the first sheath fluid sub channel  208  from the top. In some cases, the second elongated sheath fluid sub channel  212  may deliver another portion of the sheath fluid from a position located below the first sheath fluid sub channel  208  such that the sheath fluid from the second sheath fluid sub channel  212  enters the first sheath fluid sub channel  208  from the bottom. The combination of the processed sample entering the first sheath fluid sub channel  208  from the side coupled with the delivery of a portion of the sheath fluid from an upper position and/or lower position may facilitate better positioning of the core within the hydrodynamic focusing region. In some cases, this configuration may provide three-dimensional hydrodynamic focusing of the processed sample within the sheath fluid, which may result in a more reliable and accurate measurement of sample properties in the optical light scattering measurement channel  182 . In the example shown, the sheath fluid carries the processed sample into the hydrodynamic focusing region  190  for hydrodynamic focusing of the processed sample and analysis by flow cytometry. The processed sample then passes from the optical scattering measurement channel  192  into a waste channel  222  where it is carried to a waste storage reservoir  226 . In some cases, the waste storage reservoir  226  may be a self-contained, on-card waste storage reservoir. 
     In some cases, and as discussed above, the cartridge  150  may include an optical absorbance measurement region  162  including an optical absorbance measurement channel  230 . In some cases, as least a portion of the optical absorbance measurement region  162  including the optical absorbance measurement channel  230  may pass over and/or under the optical light scattering measurement region  156 , including the optical scattering measurement channel  192 , but this is not required. According to an illustrative embodiment, the optical absorbance measurement channel  230  may include at least one sub channel “ 232 ” having a cuvette “ 234 ”, including a transparent window “ 236 ”. In some cases, as shown, the optical absorbance measurement channel  230  may include multiple sub channels  232   a ,  232   b , and  232   c , each of the sub channels  232   a ,  232   b , and  232   c  having a corresponding cuvette  234   a ,  234   b  and  234   c  including a transparent window  236   a ,  236   b ,  236   c , respectively, as shown. The number of sub channels “ 232 ” may be limited only by the amount of available space on the cartridge  150 . For example, in some cases, the number of sub channels “ 232 ” may range from two to five sub channels “ 232 ”. Providing an optical absorbance measurement channel  230  having multiple sub channels “ 232 ”, each sub channel “ 232 ” having a cuvette “ 234 ” including a transparent window “ 236 ” through which light may pass for the optical absorbance measurement may facilitate simultaneous measurement of, for example, the concentration of multiple analytes of interest in a blood sample. 
     In some cases, as shown, the optical absorbance measurement channel  230  may include at least one gas permeable membrane  238  located downstream from of the one or more cuvettes  234   a ,  234   b , and  234   c . A vacuum port  240  may be located downstream from the gas permeable membrane  238  such that the gas permeable membrane  238  is positioned between the vacuum port  240  and the cuvettes  234   a ,  234   b , and  234   c . In some cases, each of the sub channels  232   a ,  232   b , and  232   c  may include a gas permeable membrane associated with each of the sub channels  232   a ,  232   b , and  232   c , where the gas permeable membrane is located downstream from each of the cuvettes  234   a ,  234   b , and  234   c . In some embodiments, each of the sub channels  232   a ,  232   b , and  232   c  may be in fluid communication with different vacuum ports located downstream from the gas permeable membranes, each of the different vacuum ports may be associated with one of the sub channels  232   a ,  232   b ,  232   c , respectively. In other embodiments, at least some of the sub channels  232   a ,  232   b , and  232   c  may be in fluid communication with a common vacuum port located downstream from the corresponding gas permeable membranes. 
     As shown in the illustrative embodiment provided by  FIG. 3 , the optical absorbance measurement channel  230  may include an on-card plasma separation region  242  to separate out the plasma portion of the fluid sample, and deliver the plasma portion of the fluid sample to one or more of the cuvettes  234   a ,  234   b , and  234   c . An exemplary on-card plasma separation region is shown and described in U.S. Provisional Application No. 61/446,924, filed on Feb. 25, 2011 entitled “SEPARATION, QUANTIFICATION AND CONTINUOUS PREPARATION OF PLASMA FOR USE IN A COLORIMETRIC ASSAY IN MICROFLUIDIC FORMAT,” which is incorporated by reference herein in its entirety for all purposes. In the illustrative embodiment, the on-card plasma separation region  242  includes a plasma separation membrane or filter  243 . In some cases, the flow of blood into and out of the plasma separation membrane  243  occurs in a transverse direction. As such, the membrane  243  may be positioned above the optical absorbance measurement channel  230 , and a negative pressure may be applied from underneath the membrane  243  to pull the blood through the membrane  243  and plasma into each of the sub channels  232   a ,  232   b , and  232   c.    
     In the illustrative cartridge of  FIG. 3 , fluid sample may be introduced into the second sample loading channel  174  via the second sample introduction port  158 . In some cases, the fluid sample may be a whole blood sample, but this is not required. The fluid sample may be then pulled through the sample loading channel  174  and into the optical absorbance measurement channel  230  by the application of a negative pressure to the vacuum port  240  provided in the cartridge  150 . In some cases, the fluid sample may also be pulled through the on-card plasma separation region  242 , before being accumulated in each of the cuvettes  234   a ,  234   b ,  234   c  for measurement using optical absorbance techniques. The sample may be pulled through the measurement channel  230  until the each of the sub channels  232   a ,  232   b ,  232   c , including the cuvettes  234   a ,  234   b , and  234   c , are filled or substantially filled, and the fluid sample contacts the gas permeable membrane  238 . The fluid sample may not pass through the at least one gas permeable membrane  238 . 
       FIG. 4  is a front schematic view of an illustrative fluid analysis cartridge  250  that may be received by a sample analyzer, such as the sample analyzer  12  of  FIG. 1 . In some embodiments, the cartridge  250  may be a disposable blood analysis cartridge configured to receive and retain a blood sample therein for analysis. As shown in  FIG. 4 , the cartridge  250  may be configured for optical light scattering measurements, and may include a hydrodynamic focusing region  256  and at least one optical light scattering measurement channel  252 . At least one optical absorbance measurement channel, such as discussed above, may also be incorporated into the cartridge  250  depending upon the desired application, but this is not required. 
     As illustrated, cartridge  250  may include a sample introduction port  262  for receiving a fluid sample. In some cases, the fluid sample may be a whole blood sample. In some cases, the fluid sample may be obtained via a finger stick or blood draw. In the case in which the fluid sample is obtained via a finger stick, the blood may be collected by the cartridge directly from the patient&#39;s finger. In the case where the fluid sample is collected by a blood draw, sample may be obtained from the sample collection tube used to collect the fluid sample, and may be injected via a syringe or the like into the cartridge  250  via the sample introduction port  262 . These are just some examples. 
     The sample introduction port  262  may be fluidly coupled to a sample collection reservoir  268  configured to receive and retain the fluid sample introduced through the sample introduction port  262 . The sample collection reservoir  268  has a reservoir volume that is defined by its inner surfaces  274 , and may have converging inner sidewalls  276  as shown in the illustrative embodiment. In some cases, the reservoir volume may be greater than a sample volume required for analysis. Sample may be drawn from the sample introduction port  262  into the sample collection reservoir  268  via capillary action. In some cases, the inner surfaces  274  of the sample collection reservoir  268  may be hydrophilic, and may in some cases include a hydrophilic surface treatment or coating disposed over at least a part of the inner surfaces  274  to facilitate capillary action. An anti-coagulant coating or surface treatment may also be disposed over at least a part of the inner surfaces  274  of the sample collection reservoir  268  in addition to or as an alternative to the hydrophilic surface treatment or coating, but this is not required. The converging inner sidewalls  276 , which may converge in a direction away from the sample collection reservoir  268 , may also help draw the fluid sample into the sample collection reservoir  268 . 
     As shown in the illustrative example of  FIG. 4 , the cartridge  250  may include a sample loading channel  280  positioned downstream from and in fluid communication with the sample collection reservoir  268 . In some cases, the cartridge  250  may include a valve  286  disposed between the sample collection reservoir  268  and the sample loading channel  280 . In some cases, the cartridge may include one or more additional sample loading channels (not shown) in fluid communication with the sample collection reservoir. In such an instance, the valve  286  also may be disposed between the sample collection reservoir  268  and the one or more additional sample loading channels such that the valve  286  is common to both the sample loading channel  280  and any additional sample loading channels incorporated into the cartridge  250 . 
     The valve  286  may include an inlet port (not visible) in fluid communication with the sample collection reservoir  268  and an outlet port (not visible) in fluid communication with the sample loading channel  280 . The valve  286  may be configured to transition between an open state in which the sample collection reservoir  268  is placed in fluid communication with the sample loading channel  280 , and a closed state in which the sample collection reservoir  268  is not in fluid communication with the sample loading channel  280 . When in the closed state, the valve may prevent back flow of sample contained within the sample loading channel  280  back into the sample collection reservoir and out the sample introduction port  262 . In some cases, the valve  286  may be actuated between its open and closed state by an actuator provided on the sample analyzer (e.g. sample analyzer  12 ) for this purpose, as will be described in greater detail below. 
       FIGS. 5A and 5B  are partial side cross-sectional views of the illustrative cartridge shown in  FIG. 4 , taken along line  5 - 5 .  FIGS. 5A and 5B  are not to scale.  FIG. 5A  depicts an illustrative valve  286  in an open state, and  FIG. 5B  depicts the illustrative valve  286  in a closed state. The valve shown in  FIGS. 5A and 5B  may be considered a pinch valve. As shown, the valve  286  may include a flexible portion  290  formed in a separate layer of the multi-layer cartridge  250 , and may include a flexible material or membrane. The flexible portion  290  may be configured to flex between the open state ( FIG. 5A ) and the closed state ( FIG. 5B ) when pressure is applied. It is contemplated that the flexible portion  290  may have a variety of shapes and/or configurations such that in the open state the flexible portion  290  facilitates fluid flow between the sample collection reservoir  268  and the sample loading channel  280 , and in the closed state the flexible portion  290  prevents or substantially prevents (less than 10% flow, less than 5% flow, less than 1% flow, relative to a fully open valve) flow between the sample collection reservoir  268  and the sample loading channel  280 . In some cases, in the closed state, the flexible portion  290  prevents or substantially prevents less than about 1% fluid flow relative to a fully open valve. 
     The valve  286  may include an inlet port  292  and an outlet port  296 . As shown in  FIG. 5A , when in the open state, the fluid sample may flow from the sample collection reservoir  268 , through the inlet port  292  of the valve  286 , and then from the valve  286  into the sample loading channel  280  via the outlet port  296  of the valve  286 . In some embodiments, such as shown in  FIG. 5B , the actuator  300  located on the sample analyzer (e.g. sample analyzer  12 ) may be configured to contact and apply a downward pressure to the flexible portion  290  of the valve  286 , causing the valve to depress, transitioning the valve  286  from the open state ( FIG. 5A ) to the closed state ( FIG. 5B ). The actuator  300  may be a plunger as shown, or may merely be an applied pressure (e.g. air pressure). As shown in  FIG. 5B , in the closed state, the flexible portion  290  may block the inlet port  292  and/or the outlet port  296  to prevent fluid flow between the sample collection reservoir  268  and the sample loading channel  280 . 
     Referring back to  FIG. 4 , cartridge  250  may include at least one vacuum port  306 , and at least one gas permeable membrane  312  situated between the vacuum port  306  and the sample loading channel  280 . In some embodiments, sample may be initially drawn into the sample collection reservoir  268  via capillary action, as discussed above, and then pulled from the sample collection reservoir  268  through the valve  286  (in the open state) and into the sample loading channel  280  by application of a negative pressure to the cartridge  250  via the vacuum port  306 . In some cases, a negative pressure may be applied to the cartridge  250  until the sample loading channel  280  is filled and sample contacts the gas permeable membrane  312 , indicating a complete fill. In some embodiments, negative pressure may be applied to the cartridge until the sample loading channel  280  and a lower portion  282  of a reagent channel  322  is also filled and contacts the gas permeable membrane  314 . The valve  286  may then be actuated from the open position ( FIG. 5A ) to the closed position ( FIG. 5B ), as discussed above, to help prevent a backflow of fluid sample from the sample loading channel  280  into the sample collection reservoir  268 . It will be understood that because the sample collection reservoir  268  may be configured to collect a greater sample volume than may be needed for analysis, a portion of the collected sample may remain in the sample collection reservoir  268  after the fluid sample has been pulled into the sample loading channel  280 , but this is not required. As such, in some cases, a second pinch valve or other sealing element may be provided to seal the sample collection reservoir  268 , but this is not required. 
     With the valve  286  closed, a pusher fluid may be introduced into the sample loading channel  280  via a pusher fluid introduction port  319  to move the fluid sample from the sample loading channel  280  to another region of the cartridge  250  for analysis. For example, as shown in  FIG. 4 , the fluid sample may be moved or pushed from the sample loading channel  280  into a reagent channel  322  including a mixing region  326 . In the reagent channel  322 , the fluid sample may be contacted with one or more reagents (e.g. lysing agent, sphering agent, diluent, etc.) introduced into the reagent channel via a reagent introduction port  318  where it may be processed for analysis. It will be understood that the number and/or type of reagents to be introduced into the reagent channel  322  may depend upon the application. The processed fluid sample may be then delivered from the mixing region  326  to the optical light scattering measurement channel  252  including a hydrodynamic focusing region  256  for analysis using, for example, flow cytometry. 
     The optical light scattering measurement channel  252  may be similar to that discussed above in reference to  FIG. 3 . The optical light scattering measurement channel  252  may include a sheath fluid introduction port  334  in fluid communication with, for example, a bifurcated sheath fluid delivery channel  336  including a first elongated sheath fluid sub channel  338  and a second elongated sheath fluid sub channel  342 . The processed sample may be introduced into the first elongated sheath fluid channel  338  from the side at an intersecting region  344 . In some cases, as shown, the processed sample may be introduced into first elongated sheath fluid sub channel at an angle, a, of approximately 90 degrees, relative to the direction of flow of the sheath fluid. It is contemplated that the processed sample may be introduced into first elongated sheath fluid sub channel at an angle, a, of between 5 and 175 degrees, between 25 and 115 degrees, between 45 and 135 degrees, between 60 and 150 degrees, between 85 and 95 degrees, or any other suitable angle relative to the direction of flow of the sheath fluid. This can be the case where only a single sheath fluid delivery channel is provided (not shown in  FIG. 4 ), or a bifurcated sheath fluid delivery channel  336  is provided (as shown in  FIG. 4 ). 
     When provided, the second elongated sheath fluid sub channel  342  may intersect with the first elongated sheath fluid sub channel  338  at a second intersection region  346  located downstream from the first intersection region  344 . In some cases, as shown, the second elongated sheath fluid sub channel  342  may deliver a portion of the sheath fluid from a position located above the first sheath fluid sub channel  338  such that the sheath fluid from the second sheath fluid sub channel  342  enters the first sheath fluid sub channel  338  from the top. In some cases, the second elongated sheath fluid sub channel  342  may deliver another portion of the sheath fluid from a position located below the first sheath fluid sub channel  338  such that the sheath fluid from the second sheath fluid sub channel  342  enters the first sheath fluid sub channel  338  from the bottom. The combination of the processed sample entering the first sheath fluid sub channel  338  from the side coupled with the delivery of a portion of the sheath fluid from an upper position and/or lower position may facilitate better positioning of the fluid sample core within the hydrodynamic focusing region. In some cases, this configuration may provide three-dimensional hydrodynamic focusing of the processed sample within the sheath fluid, which may result in more reliable and accurate measurement of the sample properties in the optical light scattering measurement channel  252 . In the example shown, the sheath fluid carries the processed fluid sample into the hydrodynamic focusing region  256  for hydrodynamic focusing of the processed sample and analysis by flow cytometry. The processed fluid sample may then pass from the optical scattering measurement channel  252  into a waste channel  348  where it may be carried to a waste storage reservoir  350 . In some embodiments, the waste storage reservoir  350  may be an on-card waste storage reservoir configured to collect and retain the waste fluid in the cartridge  250  until disposal of the cartridge in an appropriate waste receptacle. 
       FIG. 6  is a front schematic view of an illustrative fluid analysis cartridge  352  that may be received by a sample analyzer, such as the sample analyzer  12  of  FIG. 1 . In some embodiments, the cartridge  352  may be a disposable blood analysis cartridge configured to receive and retain a blood sample therein for analysis. As shown in  FIG. 6 , the cartridge  352  may be configured for optical light scattering measurements and optical absorbance measurements. For example, in  FIG. 6 , the cartridge  352  may include at least one optical light scattering measurement channel  356  having a hydrodynamic focusing region  360  disposed below a transparent window  364  for optical light scattering measurements, and an optical absorbance measurement channel  368  including at least one cuvette  372  for optical absorbance measurements. It will be understood that additional optical light scattering measurement channels and/or additional optical absorbance measurement channels may be incorporated into the cartridge  352  depending on the application. In some embodiments, the optical absorbance measurement channel  368  may include one or more sub channels, each sub channel having a cuvette as discussed above with reference to  FIG. 3 , but this is not required. Additionally, in some embodiments, the optical absorbance measurement channel  368  may include an on-card plasma separation region, as discussed above, through which the fluid sample may be passed to separate the plasma portion of the fluid sample such that the plasma portion of the fluid sample may be collected in the cuvette  372  for the optical absorbance measurement. 
     As illustrated, cartridge  352  may include a sample introduction port  376  for receiving a fluid sample. In some cases, the fluid sample may be a whole blood sample. The fluid sample may be obtained via a finger stick or blood draw. In the case in which the fluid sample is obtained via a finger stick, the blood may be collected by the cartridge  352  directly from the patient&#39;s finger. In the case where the fluid sample is collected by a blood draw, sample may be obtained from the sample collection tube used to collect the fluid sample, and may be injected via a syringe or the like into the cartridge  352  via the sample introduction port  376 . These are just some examples. 
     The sample introduction port  376  may be fluidly coupled to a sample collection reservoir  380  configured to receive and retain the fluid sample introduced through the sample introduction port  376 . The sample collection reservoir  380  has a reservoir volume that is defined by its inner surfaces  384 , and may have converging inner sidewalls  386  as shown in the illustrative example. In some cases, the reservoir volume may be greater than a sample volume required for analysis. Sample may be drawn from the sample introduction port  376  into the sample collection reservoir  380  via capillary action. In some cases, the inner surfaces  384  of the sample collection reservoir  380  may be hydrophilic, and in some cases, may include a hydrophilic surface treatment or coating disposed over at least a part of the inner surfaces  384  to facilitate capillary action. An anti-coagulant coating or surface treatment may also be disposed over at least a part of the inner surfaces  384  of the sample collection reservoir  380  in addition to or as an alternative to the hydrophilic surface treatment or coating, but this is not required. The converging inner sidewalls  386 , which may converge in a direction away from the sample collection reservoir  376 , may also help draw the fluid sample into the sample collection reservoir  380 . 
     As shown in the illustrative example of  FIG. 6 , the cartridge  352  may include a sample loading channel  388  positioned downstream from and in fluid communication with the sample collection reservoir  380 . In addition, the cartridge  352  may also include a valve  392  disposed between the sample collection reservoir  380  and the sample loading channel  388 . In some embodiments, the valve  392  may also be disposed between the sample collection reservoir  380  and an optical absorbance measurement channel  368  as shown in  FIG. 6 , such that the valve  392  is common to both the sample loading channel  388  and the optical absorbance measurement channel  368 . Additionally, in some cases, the cartridge  352  may include one or more additional sample loading channels (not shown) in fluid communication with the sample collection reservoir  380 . In such an instance, the valve  392  also may be disposed between the sample collection reservoir  380  and the one or more additional sample loading channels such that the valve  392  is common to both the sample loading channel  388  and any additional sample loading channels incorporated into the cartridge  352 . 
     The valve  392  may be similar to the valve  286  shown and described with reference to FIGS.  4  and  5 A- 5 B, and may include the same or similar features. In the illustrative embodiment shown in  FIG. 6 , the valve  392  may include an inlet port in fluid communication with the sample collection reservoir  380 , and an outlet port in fluid communication with the sample loading channel  388  and/or the absorbance measurement channel  368 . The valve  392  may be configured to transition between an open state, in which the sample collection reservoir  380  is placed in fluid communication with the sample loading channel  380  and/or the absorbance measurement channel  368 , and a closed state in which the sample collection reservoir  380  is not in fluid communication with the sample loading channel  388  and/or the absorbance measurement channel  368 . When in the closed state, the valve  392  may prevent back flow of sample contained within the sample loading channel  388  and/or the absorbance measurement channel  368  from entering back into the sample collection reservoir  380 . In some cases, the valve  392  may be actuated between its open and closed state by an actuator (e.g. plunger and/or pressure source) provided by the sample analyzer (e.g. sample analyzer  12 ) for this purpose, as discussed in greater detail above with reference to  FIGS. 5A and 5B . 
     In some cases, as shown in  FIG. 6 , the cartridge  352  may include a first vacuum port  396 , and first gas permeable membrane  402  situated between the first vacuum port  396  and the sample loading channel  388 . In some cases, the cartridge  352  may also include a second vacuum port  412  in fluid communication with the optical absorbance measurement channel  368  and a second gas permeable membrane  416  situated downstream of the cuvette  372  between the cuvette  372  and the second vacuum port  412 . In the illustrative embodiment of  FIG. 6 , the fluid sample may be initially drawn into the sample collection reservoir  380  via capillary action. A portion of the fluid sample may then be pulled from the sample collection reservoir  380  through the valve  392  and into the sample loading channel  388  by application of a negative pressure to the cartridge  352  via the first vacuum port  396 . In some cases, the fluid sample may be pulled from the sample collection reservoir  380  such that it substantially fills the sample loading channel  388  and a lower portion  390  of a reagent channel  422 , as shown in  FIG. 6 . In addition, a portion of the fluid sample may be pulled from the sample collection reservoir  380  through the valve  392  and into the absorbance measurement channel  368  by application of a negative pressure to the cartridge  352  via the second vacuum port  412 . The negative pressure may be applied to the first and second vacuum ports  396  and  412  at the same time or at different times (e.g. in a sequential manner) to pull sample from the sample collection reservoir  380  into the sample loading channel  388  and/or the absorbance measurement channel  368 , as desired. 
     In some cases, a negative pressure may be applied to the cartridge  352  until the sample loading channel  388  is filled and sample contacts the first gas permeable membrane  402 , indicating a complete fill. Additionally, a negative pressure may be applied to the cartridge  352  until the absorbance measurement channel  368  including cuvette  372  is completely filled and the fluid sample contacts the second gas permeable membrane  416 . The valve  392  may then be actuated from an open position to a closed position, as discussed above, to help prevent a backflow of fluid sample from the sample loading channel  388  and/or the absorbance measurement channel  368  back into the sample collection reservoir  380 . It will be understood that because the sample collection reservoir  380  may be configured to collect a greater sample volume than may be needed for analysis, a portion of the collected sample may remain in the sample collection reservoir  380  after the fluid sample has been pulled into the sample loading channel  388 . As such, in some cases, a second pinch valve or other sealing element may be provided to seal the sample collection reservoir  380 , if desired. 
       FIG. 7  shows a partial, cross-section view a portion of the cartridge  352  including a gas permeable membrane such as, for example, first gas permeable membrane  402  disposed between the sample loading channel  388  and the first vacuum port  396 . As shown in  FIG. 7 , application of a negative pressure  401  behind the gas permeable membrane  402  may be used to pull the fluid sample from the sample collection reservoir  380  (not visible in this figure) into the sample loading channel  388  until the fluid sample contacts the gas permeable membrane on the side opposite to negative pressure side. As discussed above, a pusher fluid P may be then introduced through the pusher fluid introduction port  418 , and may be used to push the fluid sample from the sample loading channel  388  to another region of the cartridge  352  for analysis. The pusher fluid introduction port  418  may be sealed when the negative pressure  401  is applied behind the gas permeable membrane  402 . Alternatively, the negative pressure  401  may be used to draw in pusher fluid P up to the gas permeable membrane  402 , along with the fluid sample. 
     The ability to pull a fluid sample into the sample loading channel  388  up to the gas permeable membrane  402  may help reduce any air within the sample loading channel  388 , and may help minimize any sample-air-pusher fluid interface. Additionally, the ability to pull a fluid sample into the sample loading channel  388  up to the gas permeable membrane  402  may minimize the presence of tiny air bubbles in the sample fluid, which may negatively impact the reliability and/or accuracy of the analysis performed by the cartridge. 
     Referring back to  FIG. 6 , a pusher fluid may be introduced into the sample loading channel  388  via a pusher fluid introduction port  418 , which may move the fluid sample from the sample loading channel  388  to another region of the cartridge  352  for analysis. The fluid sample may be moved or pushed from the sample loading channel  388  into a reagent channel  422  including a mixing region  426 . In the reagent channel  422 , the fluid sample may be contacted with one or more reagents (e.g. lysing agent, sphering agent, diluent, etc.) introduced into the reagent channel  422  via a reagent introduction port  430  where it may be processed for analysis. It will be understood that the number and/or type of reagents to be introduced into the reagent channel  422  may depend upon the application. The processed fluid sample may be then delivered from the reagent channel  422  to the optical light scattering measurement channel  356  for analysis using, for example, flow cytometry. 
     The optical light scattering measurement channel  356  may be similar to that discussed above in reference to  FIG. 3 . The optical light scattering measurement channel  356  may include a sheath fluid introduction port  434  in fluid communication with a bifurcated sheath fluid delivery channel  436  including a first elongated sheath fluid sub channel  438  and a second elongated sheath fluid sub channel  442 . The processed fluid sample may be introduced into the first elongated sheath fluid channel  438  from the side at an intersecting region  444 . In some cases, as shown, the processed fluid sample may be introduced into first elongated sheath fluid sub channel  438  at an angle, a, of for example approximately 90 degrees. Other angles are also contemplated. The second elongated sheath fluid sub channel  442  may intersect with the first elongated sheath fluid sub channel  438  at a second intersection region  446  located downstream from the first intersection region  444 . In some cases, as shown, the second elongated sheath fluid sub channel  442  may deliver a portion of the sheath fluid from a position located above the first sheath fluid sub channel  438  such that the sheath fluid from the second sheath fluid sub channel  442  enters the first sheath fluid sub channel  438  from the top. In some cases, the second elongated sheath fluid sub channel  442  may deliver another portion of the sheath fluid from a position located below the first sheath fluid sub channel  438  such that the sheath fluid from the second sheath fluid sub channel  442  enters the first sheath fluid sub channel  438  from the bottom. The combination of the processed fluid sample entering the first sheath fluid sub channel  438  from the side coupled with the delivery of a portion of the sheath fluid from an upper position and/or lower position may facilitate better positioning of the fluid sample core within the hydrodynamic focusing region  360 . In some cases, this configuration may provide three-dimensional hydrodynamic focusing of the processed sample within the sheath fluid, which may result in more reliable and/or accurate measurement of the sample properties in the optical light scattering measurement channel  356 . In the example shown, the sheath fluid carries the processed sample into the hydrodynamic focusing region  364  for hydrodynamic focusing of the processed sample and analysis by flow cytometry. The processed fluid sample may then pass from the optical scattering measurement channel  356  into a waste channel  448  where it may be carried to a waste storage reservoir  450 . In some embodiments, the waste storage reservoir  450  may be an on-card waste storage reservoir configured to collect and retain the waste fluid for disposal in an appropriate waste receptacle. An exemplary waste storage reservoir that may be incorporated into cartridge  352  will be described in greater detail below. 
       FIG. 8  is a front schematic view of an illustrative fluid analysis cartridge  452  that may be received by a sample analyzer, such as the sample analyzer  12  of  FIG. 1 . In some embodiments, the cartridge  452  may be a disposable blood analysis cartridge configured to receive and retain a blood sample therein for analysis. As shown in  FIG. 8 , the cartridge  452  may be configured for optical light scattering measurements and optical absorbance measurements, but this is not required. For example, as shown, the cartridge  452  may include at least one optical light scattering measurement channel  456  having a hydrodynamic focusing channel  360  disposed below a transparent window  464  for optical light scattering measurements, and an optical absorbance measurement channel  468  including at least one cuvette  472  for optical absorbance measurements. It will be understood that additional optical light scattering measurement channels and/or additional optical absorbance measurement channels may be incorporated into the cartridge  452  depending upon the application. Additionally, in some embodiments, the optical absorbance measurement channel  468  may include one or more sub channels, each sub channel having a cuvette as discussed above in reference to  FIG. 3 , but this is not required. 
     As illustrated, cartridge  452  may include a sample introduction port  476  for receiving a fluid sample. In some cases, the fluid sample may be a whole blood sample. The fluid sample may be obtained via a finger stick or blood draw. In the case in which the fluid sample is obtained via a finger stick, the blood may be collected by the cartridge  452  directly from the patient&#39;s finger. In the case where the fluid sample is collected by a blood draw, the fluid sample may be obtained from the sample collection tube used to collect the fluid sample, and may be injected via a syringe or the like into the cartridge  452  via the sample introduction port  476 . These are just some examples. 
     The sample introduction port  476  may be fluidly coupled to a sample collection reservoir  480  configured to receive and retain the fluid sample introduced through the sample introduction port  476 . The sample collection reservoir  480  has a reservoir volume that is defined by its inner surfaces  484 , and may have converging inner sidewalls  486  as shown in the illustrative example. In some cases, the reservoir volume may be greater than a sample volume required for analysis. Sample may be drawn from the sample introduction port  476  into the sample collection reservoir  480  via capillary action. In some cases, the inner surfaces  484  of the sample collection reservoir  480  may be hydrophilic, and may include a hydrophilic surface treatment or coating disposed over at least a part of the inner surfaces  484  to facilitate capillary action. An anti-coagulant coating or surface treatment may also be disposed over at least a part of the inner surfaces  484  of the sample collection reservoir  480  in addition to or as an alternative to the hydrophilic surface treatment or coating, but this is not required. The converging inner sidewalls  486 , which may converge in a direction away from the sample collection reservoir  476 , may also help draw the fluid sample into the sample collection reservoir  480 . 
     As shown in  FIG. 8 , the cartridge  452  may include a sample loading channel  488  positioned downstream from and in fluid communication with the sample collection reservoir  480 . In addition, the cartridge  452  may include a valve  492  disposed between the sample collection reservoir  480  and the sample loading channel  488 . In some embodiments, the valve  492  may also be disposed between the sample collection reservoir  480  and an optical absorbance measurement channel  468  as shown in  FIG. 8  such that the valve  492  is common to both the sample loading channel  488  and the optical absorbance measurement channel  468 , but this is not required. 
     The valve  492  may be similar to the valve  286  shown and described with reference to FIGS.  4  and  5 A- 5 B, and may include the same or similar features. In the illustrative embodiment of  FIG. 8 , the valve  492  may include an inlet port in fluid communication with the sample collection reservoir  480  and an outlet port in fluid communication with the sample loading channel  488  and the absorbance measurement channel  468 . The valve  492  may be configured to transition between an open state in which the sample collection reservoir  480  is placed in fluid communication with the sample loading channel  480  and the absorbance measurement channel  468 , and a closed state in which the sample collection reservoir  480  is not in fluid communication with the sample loading channel  488  and the absorbance measurement channel  468 . When in the closed state, the valve  492  may help prevent back flow of sample contained within the sample loading channel  488  and/or the absorbance measurement channel  368  into the sample collection reservoir  488 . In some cases, the valve  492  may be actuated between its open and closed state by an actuator provided by the sample analyzer (e.g. sample analyzer  12 ) for this purpose, as discussed in greater detail above with reference to  FIGS. 5A and 5B . 
     In some cases, and as shown in  FIG. 8 , the cartridge  452  may include a vacuum port  496  and first gas permeable membrane  502  situated between the vacuum port  496  and the sample loading channel  488 . Additionally, the cartridge  452  may also include a second gas permeable membrane  508  situated between the vacuum port  496  and the absorbance measurement channel  468 , such that the vacuum port  496  is in fluid communication with both the sample loading channel  488  and the absorbance measurement channel  468 . As shown in  FIG. 8 , the second gas permeable membrane  508  is located downstream of the cuvette  472 , and between the cuvette  472  and the vacuum port  496 . In the illustrative embodiment, the vacuum port  496  is common to both the sample loading channel  488  and the absorbance measurement channel  468 , but this is not required. For example, separate vacuum ports may be provided, if desired. 
     The fluid sample may be initially drawn into the sample collection reservoir  480  via capillary action, as discussed above, and then a portion of the fluid sample may pulled from the sample collection reservoir  480  through the valve  492  and into the sample loading channel  388  by application of a negative pressure to the cartridge  452  via common vacuum port  496  until the fluid sample reaches the gas permeable membrane  502 . In some cases, the negative pressure may be applied to the cartridge  452  until a portion of the fluid sample is pulled through the sample loading channel  488  and into a lower region  510  of a reagent channel  514  until it again reaches the gas permeable membrane  502 . Pulling a portion of the fluid sample through the sample loading channel  488  and into a lower region  510  of the reagent channel  514  may facilitate an improved liquid-liquid interface between the fluid sample and a reagent introduced into the reagent channel  514 . 
     In some cases, a portion of the fluid sample may also be pulled from the sample collection reservoir  480  through the valve  492  and into the absorbance measurement channel  468  by application of a negative pressure to the cartridge  452  via the same vacuum port  496 . The negative pressure may be applied to the cartridge  452  to pull the fluid sample into the absorbance measurement channel  468  until the fluid sample fills or substantially fills the cuvette  472  and comes into contact with the second gas permeable membrane  508 . The valve  492  may then be actuated from an open position to a closed position, as discussed above, to help prevent a backflow of fluid sample from the sample loading channel  488  and/or the absorbance measurement channel  468  back into the sample collection reservoir  480 . 
     With the valve  492  closed, a pusher fluid may be introduced into the sample loading channel  488  via a pusher fluid introduction port  518  to move the fluid sample from the sample loading channel  588  to another region of the cartridge  552  for analysis. By pulling the fluid sample into the sample loading channel  488  such that it fills the entire sample loading channel  488  including the generally V-shaped region up to the gas permeable membrane  502  and across the pusher fluid introduction port  518 , the presence of air bubbles may be reduced or eliminated and the fluid sample-pusher fluid interface may be improved. The reduction and elimination of air bubbles in the fluid sample and the improved fluid sample-pusher fluid interface may positively impact the reliability and/or accuracy of the analysis to be performed. 
     The fluid sample may be moved or pushed from the sample loading channel  488  into the reagent channel  514  including a mixing region  526 . In the reagent channel  514 , the fluid sample may be contacted with one or more reagents (e.g. lysing agent, sphering agent, diluent, etc.) introduced into the reagent channel  514  via a reagent introduction port  530  where it may be processed for analysis. It will be understood that the number and/or type of reagents to be introduced into the reagent channel  514  may depend upon the application. The processed fluid sample may be then delivered from the reagent channel  514  to the optical light scattering measurement channel  456  for analysis using, for example, flow cytometry. 
     The optical light scattering measurement channel  456  may be similar to that discussed above in reference to  FIGS. 3 ,  4 , and  6 , discussed above. The optical light scattering measurement channel  456  may include a sheath fluid introduction port  534  in fluid communication with a bifurcated sheath fluid delivery channel  536  including a first elongated sheath fluid sub channel  538  and a second elongated sheath fluid sub channel  542 . While a bifurcated sheath fluid delivery channel  536  is shown in  FIG. 8 , it is contemplated that a single sheath fluid delivery channel may be used, if desired. In  FIG. 8 , the processed fluid sample may be introduced into the first elongated sheath fluid sub channel  538  from the side at an intersecting region  544 . In some cases, as shown, the processed fluid sample may be introduced into first elongated sheath fluid sub channel  538  at an angle, a, of approximately 90 degrees relative to the direction of flow of the sheath fluid. It is contemplated that the processed sample may be introduced into first elongated sheath fluid sub channel  538  at an angle, a, of between 5 and 175 degrees, between 25 and 115 degrees, between 45 and 135 degrees, between 60 and 150 degrees, between 85 and 95 degrees, or any other suitable angle relative to the direction of flow of the sheath fluid. This can be the case where only a single sheath fluid delivery channel is provided (not shown in  FIG. 8 ), or a bifurcated sheath fluid delivery channel  536  is provided (as shown in  FIG. 8 ). 
     The second elongated sheath fluid sub channel  542  may intersect with the first elongated sheath fluid sub channel  538  at a second intersection region  546  located downstream from the first intersection region  544 . In some cases, as shown, the second elongated sheath fluid sub channel  542  may deliver a portion of the sheath fluid from a position located above the first sheath fluid sub channel  538  such that the sheath fluid from the second sheath fluid sub channel  542  enters the first sheath fluid sub channel  538  from the top. In some cases, the second elongated sheath fluid sub channel  546  may deliver another portion of the sheath fluid from a position located below the first sheath fluid sub channel  538  such that the sheath fluid from the second sheath fluid sub channel  546  enters the first sheath fluid sub channel  538  from the bottom. The combination of the processed fluid sample entering the first sheath fluid sub channel  538  from the side coupled with the delivery of a portion of the sheath fluid from an upper position and/or lower position may facilitate better positioning of the fluid sample core within the hydrodynamic focusing region  460  of the optical light scattering measurement channel  456 . In some cases, this configuration may provide three-dimensional hydrodynamic focusing of the processed sample within the sheath fluid, which may result in more reliable and accurate measurement of the sample properties. In the example shown, the sheath fluid carries the processed sample into the hydrodynamic focusing region  460  for hydrodynamic focusing of the processed sample and analysis by flow cytometry. The processed fluid sample may then pass from the optical scattering measurement channel  456  into a waste channel  548  where it may be carried to a waste storage reservoir  550 . In some embodiments, the waste storage reservoir  550  may be an on-card waste storage reservoir configured to collect and retain the waste fluid for disposal in an appropriate waste receptacle. An exemplary waste storage reservoir that may be incorporated into cartridge  552  will be described in greater detail below. 
       FIG. 9  is an exploded view of the exemplary cartridge  452  shown in  FIG. 8 . As shown in  FIG. 9 , the cartridge  452  may be a multi-layered cartridge including multiple layers. In some cases, as shown, the cartridge  452  may include up to seven layers. Additional or fewer layers may be incorporated into the cartridge  452  depending upon the desired application and type of sample to be analyzed. 
     As shown in  FIG. 9 , portions of the various channels incorporated into the cartridge  452  (e.g. optical light scattering measurement channel  456 , optical absorbance measurement channel  468 , sample loading channel  488  and reagent channel  514 ) may be formed in different layers of a multi-layered cartridge  452 . In some cases, this may facilitate at least a portion of a first channel to pass over and/or under at least a portion of a second channel, as discussed above. For example, in some embodiments, at least a portion of the optical absorbance measurement channel  468  may pass over and/or under at least a portion of the optical light scattering measurement channel  456  and/or the reagent channel  514 . The ability to layer different portions of different channels may facilitate the inclusion of multiple channels for different purposes within the cartridge. Additionally, the ability to form different channels in different layers may facilitate a better usage of the available space on the cartridge  452 , which may facilitate an overall reduction in the size of the cartridge  452 . 
     For example, in some cases, a portion of the optical absorbance measurement channel  468 , the sample loading channel  488 , and the first elongated sheath fluid sub channel  538  of the optical light absorbance measurement channel  468  may be formed in a first layer  560  of the multi-layered cartridge  352 . In some cases, as shown, the first layer  560  may also include at least one transparent window  564  for facilitating the optical absorbance measurement of the fluid sample, and a first vacuum line  568  and a portion  572  of a second vacuum line  576  for applying a negative pressure to the cartridge  452  as described above. 
     In some embodiments, the valve  492  and the gas permeable membranes  502  and  508  may be provided in a separate layer  570  that may be disposed between the first layer  560 , as discussed above, and an additional layer  580  that may include the reagent channel  514 , the cuvette  472  of the optical absorbance measurement channel  468  which may be disposed under the transparent window  564  provided in the first layer  560 , the second elongated sheath fluid sub channel  542 , and a second transparent measurement window  584  that may facilitate the optical light scattering measurement. Yet another layer  590  may include the sample collection reservoir  480  and the waste channel  548 . Additionally, layer  590  may also include one or more pass-throughs  594  for passage of waste fluid some one region of the waste storage reservoir  550  to the next. 
     In some embodiments, as shown in  FIG. 9 , the waste storage reservoir  550  may be formed in a separate layer  600  of the multi-layered cartridge  452 . In some cases, the waste storage reservoir  550  may include multiple segments  550   a ,  550   b , and  550   c . The pass-throughs  594 , discussed above, may facilitate transfer of waste from a first segment (e.g. segment  550   a ) to another segment (e.g.  550   b ) of the waste storage reservoir  550 . In some embodiments, the waste storage reservoir  550  may include one or more ribs  604  that extend upwards away from a bottom of the layer  600  and which may provide additional structural integrity to the cartridge  452 . 
     Various vias  608  formed in different layers of the cartridge  452  may facilitate transfer of the liquid sample between the different layers of the cartridge  452  as the fluid sample is moved from one region of the card to another for analysis. In some cases, the location and placement of the vias  608  may facilitate the reduction and/or elimination of tiny air bubbles in the fluid sample. Additionally, one or more vias  608  provided in the cartridge  452  may facilitate the escape of air from the cartridge  452  when a negative pressure is applied such that a more complete evacuation of any air present within the cartridge may  452  be achieved. 
       FIG. 10  is a front schematic view of an illustrative fluid analysis cartridge  650  that may be received by a sample analyzer, such as the sample analyzer  12  of  FIG. 1 . In some embodiments, the cartridge  650  may be a disposable blood analysis cartridge configured to receive and retain a blood sample therein for analysis. As shown in  FIG. 10 , the cartridge  650  may include at least one optical light scattering measurement channel  656  having a hydrodynamic focusing channel  660  disposed adjacent a transparent window  664  for optical light scattering measurements. Although not shown, in some cases the cartridge  650  may also include an optical absorbance measurement channel, such as describe detail above. It will be understood that additional optical light scattering measurement channels and/or additional optical absorbance measurement channels may be incorporated into the cartridge  650 , depending upon the desired application. 
     In some cases, and as shown in  FIG. 10 , the cartridge  650  may include at least one sample introduction port  668  for introduction of a sample into the cartridge  650 . In some cases, the sample introduction port  668  may include an anti-coagulant coating provided on an inner surface thereof to facilitate sample loading. In other cases, the sample introduction port  668  may include a hydrophilic coating which may facilitate loading of the sample via capillary action. However, this is not required. In some cases, the sample introduction port may be configured to mate with and/or receive a syringe for delivery of a fluid sample into the cartridge  650 , but again, this is not required. Any suitable fluid connection for delivery of a fluid sample into the cartridge  650  may be used. 
     As illustrated in the example of  FIG. 10 , the sample introduction port  668  may be in fluid communication with a sample loading channel  670 , a reagent channel  676 , and the optical light scattering measurement channel  656 . Once a sample is loaded into the sample loading channel  670 , a pusher fluid may be introduced via the sample introduction port  668  (or some other port) to push the sample from the sample loading channel  670  into the reagent channel  676 , which in the illustrative embodiment. In some cases, the reagent channel  676  may include a reagent introduction port  680  for introduction of one or more reagents into the reagent channel  676  for processing the sample. The number and/or type of reagents to be introduced into the reagent channel  676  may depend upon the application. For example, the reagents may include a lysing reagent, a sphering reagent, a diluent, etc. The reagent introduced through the reagent introduction port  680  may contact and mix with the sample entering the reagent channel  676  from the sample loading channel  670 . In some embodiments, the reagent channel  676  may include a number of bends or turns  686  that may help increase the length of the reagent channel  676 , which may increase the length of time the sample spends in the reagent channel. In some cases, as shown, the bend or turn  686  may be a substantially U-shaped bend or turn  686 , and may help keep particles such as blood cells dispersed as the sample travels through the reagent channel  676 . The increase in dwell or residence time may provide a sufficient amount of time needed for the reagent to properly react with and process the sample for analysis. The processed sample may then delivered from the reagent channel  676  to the optical light scattering measurement channel  656  for analysis using an optical light scattering measurement technique such as, for example, flow cytometry. 
     The optical scattering measurement channel  656  may include a hydrodynamic focusing channel  660  over which a transparent window  664  may be disposed. In some cases, the length of the hydrodynamic focusing channel may be reduced, such as from 2 mm to 1.5 mm, 1.0 mm, 0.5 mm or less. This may help reduce backpressure in the optical light scattering measurement channel  656  of the cartridge  650 . 
     In the example shown, sheath fluid may be introduced into the cartridge via a sheath fluid introduction port  690 . The sheath fluid may be provided at such a flow rate that it surrounds the processed sample and forms a “sheath” around the sample “core”. In some cases, the sheath fluid flow rate may be controlled such that it is higher than the processed sample flow rate to aid in core formation downstream within the hydrodynamic focusing region  660 . As shown in  FIG. 10 , the cartridge  650  may include a single sheath fluid channel  702 , and may not include a second or bifurcated sheath fluid delivery channel, although this is not required. Utilizing a single sheath fluid channel  702  may help facilitate a reduction in the performance variation due to changes in flow balance that may be present when utilizing two sheath fluid delivery channels. A single sheath fluid delivery channel, coupled with a shorter hydrodynamic focusing channel may help facilitate stabilization of fluid sample flow within the cartridge  650 , which may in some cases increase the overall accuracy and/or the reliability of the fluid analysis. 
     In some cases, the processed sample may be delivered from the reagent channel  676  to the optical measurement channel  656  at a location upstream relative to the hydrodynamic focusing channel  660 . In some cases, as shown, the processed sample may be introduced from the reagent channel  676  into the sheath fluid channel  702  at an angle, a, of approximately 90 degrees relative to the direction of flow  657  of the sheath fluid. It is contemplated that the processed sample may be introduced from the reagent channel  676  into the sheath fluid channel  702  at an angle, a, of between 5 and 175 degrees, between 25 and 115 degrees, between 45 and 135 degrees, between 60 and 150 degrees, between 85 and 95 degrees, or any other suitable angle, relative to the direction of flow  657  of the sheath fluid. Delivery of the processed sample at such an angle may facilitate better positioning of the sample “core” within the hydrodynamic focusing channel  660 . 
     In some cases, the reagent channel  676  may undergo a bend or otherwise change direction just upstream of the optical measurement channel  656 . In some cases, such a bend or change in direction in the reagent channel  676  may cause the processed sample to rotate about 90 degrees just upstream of the optical measurement channel  656 . In some cases, this may move the cell stream from the floor of the reagent channel  676  to the side wall. In some cases, this rotation may place the cells away from the ceiling and floor of the optical measurement channel  656  for better core formation. Once injected into the optical scattering measurement channel  656 , the processed sample may be carried by the sheath fluid through the optical scattering measurement channel  656  and into a waste channel  706 , where it is carried to a waste storage reservoir  710 . 
     In some cases, the waste storage reservoir  710  may be a self-contained, on-card waste storage reservoir. In some cases, the waste channel  706  may commute between different layers of the laminated cartridge  650 , which may increase the overall structural integrity of the cartridge  650  during manufacture. Additionally, the waste storage reservoir  710  may include a capillary groove on an inner surface thereof, which may help prevent waste fluid aggregation. 
     In some cases, the cartridge  650  may include one or more vias  714 , sometimes having a reduced cross-section relative to the flow channels between which they are disposed. Such vias  714  may be located throughout the cartridge and may be disposed between two regions of a single channel and/or two different fluid channels on the cartridge. In some instances, for example, a via  714  having a reduced cross-sectional area relative to part of the waste channel  706  in one layer of the laminated cartridge  650  to another part of the waste channel  706  in another layer of the laminated cartridge  650 . In another example, a via  715  having a reduced cross-sectional area relative to part of the sheath fluid channel  702  in one layer of the laminated cartridge  650  to another part of the sheath fluid channel  702  in another layer of the laminated cartridge  650 . In some cases, this may help reduce the frequency of air bubbles in the sheath fluid channel  702  downstream of via  715 . 
     The cartridges, as discussed herein according to the various embodiments may be formed by any of the techniques known in the art, including molding, machining, and etching. The various cartridges can be made of materials such as metal, silicon, plastics, and polymers, and combinations thereof. In some cases, the cartridges may be formed from a single sheet, from two sheets, or from a plurality of laminated sheets. The individual sheets forming the multi-layered cartridges of the present disclosure need not be formed from the same material. For example, different layers may have different rigidities such that a more rigid layer may be used to strengthen the overall structural integrity of the exemplary cartridges while a more flexible layer or portion of a layer may be used to form at least a portion of the valve structure as described herein. The various channels and flow regions of the cartridge may be formed in different layers and/or the same layer of an exemplary cartridge. The different channels and/or ports may be machined, die cut, laser ablated, etched, and/or molded. The different sheets forming the laminated structure may be bonded together using an adhesive or other bonding means. 
     Having thus described several illustrative embodiments of the present disclosure, those of skill in the art will readily appreciate that yet other embodiments may be made and used within the scope of the claims hereto attached. Numerous advantages of the disclosure covered by this document have been set forth in the foregoing description. It will be understood, however, that this disclosure is, in many respect, only illustrative. Changes may be made in details, particularly in matters of shape, size, and arrangement of parts without exceeding the scope of the disclosure. The disclosure&#39;s scope is, of course, defined in the language in which the appended claims are expressed.