Patent Publication Number: US-2022212191-A1

Title: System for delivering fluid samples through a fluidic device and methods therefor

Description:
This application claims the benefit of provisional patent application Ser. No. 62/823,817, filed on Mar. 26, 2019, the entire contents of which are hereby incorporated herein by reference. 
    
    
     FIELD 
     This application relates generally to fluidic devices and, in particular, to a system and method for delivering a fluid sample through a fluidic device, such as a diagnostic consumable. 
     BACKGROUND 
     Fluidic devices are used to control and/or manipulate fluids for any of a variety of applications. A fluidic device could include channels that constrain the flow of a fluid in the device. A channel could be considered a microchannel if at least one dimension of the channel (a radius, width or height, for example) is sub-millimeter, and/or if the channel carries sub-milliliter volumes of fluid. A fluidic device that includes a microchannel, and/or other microscale components, could be considered a microfluidic device. 
     Fluidic devices could incorporate and/or be coupled to one or more sensors to provide sensing capabilities. For example, a sample fluid could be delivered through channels in a fluidic device to a sensing region of the fluidic device in order to be exposed to a sensor. The sensor could be incorporated into the fluidic device and/or part of a separate device to which the sensing region is exposed in order to measure one or more properties of the fluid. A fluidic device that incorporates one or more sensors or sensing regions could be used as a diagnostic device. In the context of medical diagnostic devices, fluidic devices could be used in the measurement of one or more properties of a bodily fluid. By way of example, a blood sample could be added to a fluidic device to control and/or manipulate the blood sample in order to measure the concentration of certain analytes in the blood. 
     In recent years, miniature fluidic devices have attracted attention for use in the field as diagnostic devices for point-of-care testing. A fluidic device in this field usually provides integration of multiple analytical steps into a single device. A fluidic device may perform one or more assays. For the purposes of the instant disclosure, an assay may be defined as a procedure for quantifying the amount or the functional activity of an analyte in a liquid sample. An assay may involve a variety of operations on the fluidic device, such as sample introduction, preparation, metering, sample/reagent mixing, liquid transport, and detection, etc. Typical diagnostic assays involve manipulating and delivering small volumes of fluid with precise control, which can be challenging due to several factors, such as fluid loss in transport, capillary effects, impact of gravity, trapped air and others. 
     SUMMARY 
     According to an aspect of the present disclosure, there is provided a reader for reading a diagnostic consumable, the reader comprising: a reader opening for receiving the diagnostic consumable; and a delivery system configured and arranged to operatively connect to the diagnostic consumable in the reader opening for delivering a fluid sample through a channel of the diagnostic consumable, the delivery system comprising: a vacuum source, a charge vessel fluidly connected to the vacuum source upstream of the vacuum source, a first valve immediately upstream of the charge vessel, and a second valve immediately downstream of the charge vessel, wherein the first and second valves are operable to open and close at a predetermined frequency to alternatingly charge and discharge the charge vessel, thereby applying vacuum pressure pulses to the channel of the diagnostic consumable. 
     In some embodiments, the vacuum source comprises a vacuum pump. 
     In some embodiments, the reader further comprises a source vessel fluidly connected to the vacuum source and charge vessel between the vacuum source and the charge vessel, wherein a volume of the source vessel is larger than a volume of the charge vessel. 
     In some embodiments, the reader further comprises a vacuum controller configured to open and close the first and second valves at the predetermined frequency. 
     In some embodiments, the vacuum controller is further configured to vary the predetermined frequency in dependence on the viscosity of the fluid sample. 
     In some embodiments, the reader further comprises a third valve downstream of the source vessel between the source vessel and the vacuum source, wherein the third valve is operable to close when a source pressure in the source vessel has reached a predetermined vacuum pressure. 
     In some embodiments, the charge vessel is dimensioned in dependence on a viscosity range of the fluid samples to be delivered. 
     In some embodiments, the first and second valves are solenoid-type valves. 
     In some embodiments, the reader further comprises a vacuum controller configured to control the vacuum pressure provided by the vacuum source. 
     In some embodiments, the diagnostic consumable is a diagnostic card. 
     According to another aspect of the present disclosure, there is provided a method for delivering a fluid sample through a channel of a diagnostic consumable, the method comprising: receiving the diagnostic consumable in a reader comprising a delivery system, operatively connecting the delivery system to the channel, applying pressure pulses to the channel at a predetermined frequency. 
     In some embodiments, the fluid sample is a human blood sample. 
     In some embodiments, the pressure of the pressure pulses is dependent on the viscosity of the fluid sample. 
     In some embodiments, the method further comprises adjusting the predetermined frequency in dependence on the viscosity of the fluid sample, wherein the predetermined frequency is increased for more viscous fluid samples. 
     In some embodiments, the method further comprises adjusting the predetermined frequency in dependence on the speed of travel of the fluid sample within the channel. 
     In some embodiments, applying the pressure pulses to the channel comprises pressurizing a charging vessel to a predetermined pressure and fluidly connecting the pressurized charging vessel to the channel. 
     In some embodiments, applying the pressure pulses to the channel further comprises pressurizing a source vessel operably connected to the charging vessel and using the source vessel to pressurize the charging vessel, wherein a volume of the source vessel is larger than a volume of the charge vessel. 
     In some embodiments, applying the pressure pulses to the channel further comprises pressurizing the source vessel using a pressure source operably connected to the source vessel. 
     In some embodiments, the pressure source is a vacuum pump and the pressure pulses are vacuum pressure pulses. 
     In some embodiments, the method further comprises controlling a first valve and a second valve to open and close the charge vessel at the predetermined frequency to alternatingly charge and discharge the charge vessel. 
     Other aspects and features of embodiments of the present disclosure will become apparent to those ordinarily skilled in the art upon review of the following description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing summary, as well as the following detailed description of illustrative embodiments of the present application, will be better understood when read in conjunction with the appended drawings. For the purposes of illustrating the present application, there is shown in the drawings illustrative embodiments of the disclosure. It should be understood, however, that the application is not limited to the precise arrangements and instrumentalities shown. In the drawings: 
         FIG. 1  is a perspective view of a reader according to one embodiment of the present disclosure; 
         FIG. 2  is a perspective view of a reader according to another embodiment of the present disclosure; 
         FIG. 3  is an isometric view of the top of an example substrate for a diagnostic consumable; 
         FIG. 4  is an isometric view of the bottom of the substrate of  FIG. 3 ; 
         FIG. 5  is a plan view of the top of the substrate of  FIG. 3 ; 
         FIG. 6  is a plan view of the bottom of the substrate of  FIG. 3 ; 
         FIG. 7  is a plan view of the top of an example diagnostic consumable incorporating the substrate of  FIG. 3 ; 
         FIG. 8  is a plan view of the bottom of the diagnostic consumable of  FIG. 7 ; 
         FIG. 9  is a schematic view of a delivery system according to one embodiment of the present disclosure; 
         FIG. 10  is a plot of time of delivery as a function of viscosity for two different delivery system configurations, which also shows the general effect on time of delivery of changing reservoir pressure and capacitor discharge frequency; 
         FIG. 11A  is a plot of pressure within the consumable relative to atmosphere as a function of delivery time according to embodiments of the present disclosure; 
         FIG. 11B  is a magnification of a portion of the plot in  FIG. 11A ; 
         FIG. 11C  is a plot showing summation of pressure increases due to sample movement as a function of delivery time according to embodiments of the present disclosure; 
         FIG. 12  is a plot of time of delivery as a function of blood sample haematocrit for one embodiment according to the present disclosure; 
         FIG. 13  is a schematic view of a delivery system according to one embodiment of the present disclosure; 
         FIG. 14  is a photograph of components of a delivery system according to one embodiment of the present disclosure; 
         FIG. 15  is a schematic view of a control system of a reader according to one embodiment of the present disclosure; 
         FIG. 16  is a top view of the relative positioning of a diagnostic consumable and a manifold of a delivery system according to one embodiment of the present disclosure; 
         FIG. 17  is a side view of  FIG. 16 ; 
         FIG. 18  is a bottom view of  FIG. 16 ; 
         FIG. 19  is a bottom view of the manifold of  FIG. 16   
         FIG. 20  is a top perspective view of the manifold of  FIG. 16 ; 
         FIG. 21  is a top view of the manifold of  FIG. 16 ; and 
         FIG. 22  is flow diagram illustrating an example method for delivering a fluid sample through a channel of a diagnostic consumable according to one embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Fluidic devices, such as fluidic devices incorporating diagnostic assays, can receive fluid samples of varying viscosity. A sample&#39;s viscosity is related to the amount of drag the sample experiences as it is delivered through one or more channels of the fluidic device. Assuming a constant force being applied to the fluid sample, for example by a constant pressure, samples with different viscosities will take different amounts of time to travel to a desired location within the fluidic device, for example an assay region. This may be undesirable, particularly for bodily fluid samples, such as blood—where viscosity correlates with haematocrit—because sample analytes may change during the period of delivery from a sample entry region, or reservoir, to the assay region. Thus, assuming a simple external constant-pressure source is used to deliver the fluid sample to the assay region, delivery time—and, thus, the integrity of the sample—varies with viscosity. 
     Embodiments according to the present disclosure may be used to deliver fluid samples with different viscosities to predetermined and/or desired regions of the fluidic device in substantially similar times or within a range of times that is narrower than compared to a constant-pressure source delivery system, while also preventing low viscosity samples from being delivered at undesirably high speeds at which stopping the sample accurately may pose difficulties. 
     Diagnostic assays may be embodied on a consumable fluidic device, also referred to herein as a diagnostic consumable. Consumable in this sense does not necessarily mean that any portions of the device are consumed during operation, but that the device may be a sing-use diagnostic device that is not re-used. 
     Some such diagnostic consumables may be embodied as a credit card-shaped consumable that is inserted into a reader (i.e. diagnostic reading device), such as a card reader, in order to run the diagnostic. Some embodiments of the present disclosure will be described in reference to a card reader and diagnostic card that is read by the card reader. However, it will be understood that the principles of the present disclosure are applicable to other types of diagnostic consumables and fluidic devices generally, whether consumable or not. 
     According to embodiments of the present disclosure, a diagnostic consumable receives a sample that is delivered through channels of the diagnostic consumable to one or more assays or assay regions. The card reader may be used to perform one or more assays by, for example, incorporating sensors or by incorporating one or more modules, such as a processor module, that receives signals and/or data from one or more assays and/or sensors in the diagnostic consumable and processes those signals and/or data. The reader may also include one or more devices or systems that cooperate with the diagnostic consumable to deliver the sample through the channels of the diagnostic consumable. 
     Referring to  FIGS. 1 and 2 , embodiments of a reader  10  include a reader opening  12  for receiving a diagnostic consumable; a control portion  14 , including a power button  15 ; and a body  16 . In the embodiment of  FIG. 2  a display device  18  for displaying, among other things, results of one or more diagnostic tests conducted by or with the diagnostic consumable is also shown. The display device  18  may be integrally assembled with the remainder of the reader  10  or it may be a separable display device that is operably connectable to the reader  10 . The display device  18  may be inserted into a holder  20 , in which electrical connections (not shown) for power and/or data transfer are provided for connecting to the display device  18 . The display device  18  may also be a separate unit containing a processor, such as a mobile device, personal digital assistant, or other screen-enabled device. The reader  10  may be capable of a wired and/or wireless connection to the display device  18  or other device for the purposes of transmitting and/or receiving data. For example, the reader  10  may be configured to transmit data directly to a hospital records system. 
     Referring to  FIGS. 3 to 8 , one embodiment of a diagnostic consumable, such as a diagnostic consumable intended for operation with the reader  10 , will be described.  FIGS. 3 to 6  illustrate an example substrate  500  for a diagnostic consumable that includes multiple sensing regions.  FIGS. 3 and 4  are isometric views of the substrate  500 , and  FIGS. 5 and 6  are plan views of the substrate.  FIGS. 3 and 5  are views of a top surface  502  of the substrate  500 , and  FIGS. 4 and 6  are views of a bottom surface  504  of the substrate. The terms “top” and “bottom” are used herein for ease of reference only, and do not require or imply a certain orientation of the substrate  500 . Although the substrate  500  could be designed to be operated with the top surface  502  facing vertically upwards and the bottom surface  504  facing vertically downwards, this might not be the case in all implementations. Moreover, the orientation of the top surface  502  and the bottom surface  504  of the substrate  500  could have minimal or no impact on fabrication, storage and/or transportation of the substrate. 
     The substrate  500  is illustrated as being a rectangular prism that is approximately the size and shape of a credit card, but this is only an example. The substrate  500  could also or instead be other shapes such as triangular or circular, for example. The substrate  500  could be made out of plastics, ceramics, glass and/or metal, for example. The substrate  500  could be a single, unitary body or part. The dimensions of the substrate  500  are not limited to any specific ranges or values. The length and width of the substrate  500  could be considered to define the area of the top surface  502  and the bottom surface  504 . In some implementations, the length and/or width of the substrate  500  is on the order of centimeters. In some implementations, the length and/or width of the substrate  500  is on the order of millimeters. Other lengths and/or widths of the substrate  500  are also possible. The thickness of the substrate  500  could be measured as the distance between the top surface  502  and the bottom surface  504  of the substrate. In some implementations, the thickness of the substrate  500  is on the order of centimeters. In some implementations, the thickness of the substrate  500  is on the order of millimeters. In some implementations, the thickness of the substrate  500  is on the order of micrometers. Other thicknesses of the substrate  500  are also possible. Although the top surface  502  and the bottom surface  504  of the substrate  500  are illustrated as being substantially flat, this might not be the case in all embodiments. For example, the top surface and/or the bottom surface of a substrate could also or instead be triangular, conical and/or hemispherical in shape. Accordingly, the thickness of a substrate could vary along its length and/or width. The substrate  500  is illustrated as being transparent, however substrates could also or instead be, in whole or in part, translucent or opaque. 
     The substrate  500  further includes a sample fluid input port  506 , a sample fluid reservoir  508 , a fluid reservoir  510 , a valve hole  512 , two bubble traps  514 ,  516 , another sensing region  518 , waste fluid reservoirs  520 ,  543 , multiple delivery system connection ports  522 ,  523 , multiple vias  112 ,  114 ,  524 ,  526 ,  528 ,  530 ,  532 ,  534 ,  536 ,  545 , and multiple channels  538 ,  540 ,  542 ,  544 ,  546 ,  548 ,  550 ,  552 ,  554 ,  556 ,  558 ,  560 ,  562 . In  FIGS. 3 to 6 , solid lines are used to illustrate components that are directly in view in each figure, and dashed lines are used to illustrate components that are hidden from view by at least a portion of the substrate  500 . 
     The channels  538 ,  540 ,  541 ,  542 ,  544 ,  546 ,  548 ,  550 ,  552 ,  554 ,  556 ,  558 ,  560 ,  562  are provided to carry one or more fluids in the substrate  100 . The channels  540 ,  541 ,  542 ,  548 ,  552 ,  558  are trenches or grooves in the top surface  502  of the substrate  500 . The channels  540 ,  541 ,  542 ,  548 ,  552 ,  558  are illustrated as being open at the top surface  502  of the substrate  500  in  FIGS. 3 and 5 . Similarly, the channels  538 ,  544 ,  546 ,  550 ,  554 ,  556 ,  560 ,  562  are trenches or grooves in the bottom surface  504  of the substrate  500 , which are open at the bottom surface of the substrate in  FIGS. 4 and 6 . Any or all of the channels  538 ,  540 ,  541 ,  542 ,  544 ,  546 ,  548 ,  550 ,  552 ,  554 ,  556 ,  558 ,  560 ,  562  could be microfluidic channels. For example, the width and/or height of any or all of the channels  538 ,  540 ,  541 ,  542 ,  544 ,  546 ,  548 ,  550 ,  552 ,  554 ,  556 ,  558 ,  560 ,  562  could be on the order of micrometers. The width and/or height of any or all of the channels  538 ,  540 ,  541 ,  542 ,  544 ,  546 ,  548 ,  550 ,  552 ,  554 ,  556 ,  558 ,  560 ,  562  could also or instead be on the order of millimeters or centimeters. The cross-sectional area of a channel or other fluidic component is generally measured as an area inside of the channel that is perpendicular to a direction of fluid flow. Although the channels  538 ,  540 ,  541 ,  542 ,  544 ,  546 ,  548 ,  550 ,  552 ,  554 ,  556 ,  558 ,  560 ,  562  are illustrated with generally rectangular cross-sections in  FIGS. 3 to 6 , one or more of these channels could have other cross-sectional shapes as well, such as semicircular or triangular, for example. 
     The vias  112 ,  114 ,  524 ,  526 ,  528 ,  530 ,  532 ,  534 ,  536 ,  545  are through-holes or bores that extend through the substrate  500 . Vias could be used to fluidly connect two or more components of the substrate  500 . For example, via  112  fluidly connects channel  542  and a sample preparation channel  102 , via  114  fluidly connects chamber  110  and channel  541 , via  526  fluidly connects channel  538  and channel  540 , via  528  fluidly connects channel  540  and channel  544 , via  530  fluidly connects channel  552  and channel  554 , via  532  fluidly connects channel  548  and channel  556 , via  534  fluidly connects channel  546  and channel  548 , via  536  fluidly connects channel  560  and the waste fluid reservoir  520 , and via  545  fluidly connects channel  562  and the waste fluid reservoir  543 . Vias could also or instead be used to fluidly connect a component of the substrate  500  to the top surface  502  and/or bottom surface  504  of the substrate. For example, the via  524  fluidly connects the sample fluid reservoir  508  to the bottom surface  504  of the substrate  500 . Although illustrated as circular holes, the vias could also or instead be other shapes such as rectangular or triangular, for example. The diameter of the vias could be similar to the width of one or more of the components that each via connects. For example, the diameter of the via  526  could be similar to the width of the channel  538  and/or the channel  540 . However, the diameter of the vias could be different from the width of the components that each via connects. 
     The sample fluid input port  506  is provided to deliver a blood sample to the substrate  500 . The sample input port  506  is a conical or cylindrical opening in the top surface  502  of the substrate  500 . The sample input port  506  is coupled to the channel  538 . The sample input port  506  could be sized and shaped to engage with an end of a fluid sample delivery device, such as, in the case of a blood sample, a syringe or capillary tube (not shown), that delivers the blood sample. For example, in the case of a syringe, this engagement between the sample input port  506  and the syringe could form a seal such that, when the blood sample is propelled or pumped out of the syringe, the blood sample is forced into the channel  538  and does not spill out of the sample input port. In some embodiments, a gasket component is installed in the sample input port  506  in order to facilitate the sealing engagement with the sample delivery device. 
     The sample fluid reservoir  508  could be a relatively wide and long channel or chamber that is coupled to the channel  540 . The sample fluid reservoir  508  is illustrated with a rectangular cross-section, however other cross-sectional shapes are also possible. The sample fluid reservoir  508  could be provided to store a blood sample after it is delivered into the substrate  500 . The via  524  could act as an air vent to allow air to escape the sample fluid reservoir  508  when it is displaced by the addition of blood sample. During operation, the blood sample might stay in the sample fluid reservoir  508  for an amount of time that is on the order of milliseconds, seconds, or minutes, for example. 
     The fluid reservoir  510  could be a relatively wide and long channel or chamber that is coupled to the channel  550 . The fluid reservoir  510  is illustrated as a U-shaped channel with a semicircular cross-section, however other geometries are also possible. In some embodiments, the fluid reservoir  510  could be provided to store a calibration fluid or a wash fluid and/or a fluid pack that seals the calibration fluid or the wash fluid. The fluid pack could be positioned in a shallow depression provided by the fluid pack region  578 . In embodiments where the fluid reservoir  510  stores a calibration fluid, the calibration fluid could be used to calibrate one or more sensors included on and/or coupled to the substrate  500 . Calibration fluids could include fluids with known concentrations of one or more analytes. These analytes could correspond to analytes in the fluid sample, such as a blood sample, that might be measured using the substrate  500 . In embodiments where the fluid reservoir  510  stores a wash fluid, the wash fluid could be used to wash one or more regions of the substrate  500 . For example, the wash fluid could be used to wash away unbound components from an antigen-antibody interaction region. 
     The valve hole  512  could be a via or bore that extends through the thickness of the substrate  500 . The channel  550  and the channel  552  could be fluidly connected by the valve hole  512 . The valve hole  512  could be sized and shaped to accommodate and/or couple to a valve (not shown). This valve could control the flow of fluid from the channel  550  to the channel  552 . When the valve is closed, the flow of fluid between the channel  550  and the channel  552  could be blocked. When the valve is opened, the flow of fluid between the channel  550  and the channel  552  could be permitted. In some implementations, the valve could be closed until a seal in the valve is ruptured, allowing fluid to flow into the channel  552 . 
     The two bubble traps  514 ,  516  are provided to inhibit the movement of bubbles in the substrate  500 . Each bubble that enters either of the bubble traps  514 ,  516  could be prevented from moving further downstream by one or more barriers in the bubble trap. Thus, the fluid that leaves the bubble traps  514 ,  516  could be free of air bubbles. The bubble trap  514  fluidly connects the channels  544 ,  546 , and the bubble trap  516  fluidly connects the channels  554 ,  556 . 
     The sensing region  518  includes a channel that is coupled to the channel  548  and to the channel  558 . The sensing region  518  extends through the thickness of the substrate  500 , and is therefore illustrated as being open at the top surface  502  and bottom surface  504  of the substrate in  FIGS. 3 to 6 . The sensing region  518  could include and/or be coupled to one or more sensors that measure properties of fluids in the sensing region. For example, the sensors could measure the concentration of one or more analytes in a fluid that flows from the channel  548  to the channel  558 . The sensing region  518  could also or instead be referred to as an assay region. 
     The waste fluid reservoir  520  is fluidly coupled to the channel  558 , and stores fluid that has flowed through the sensing region  518 . The waste fluid reservoir  520  is illustrated in  FIGS. 3 to 6  as a meandering channel with a rectangular cross-section, however other geometries of the waste fluid reservoir  520  are also possible. 
     The delivery system connection ports  522 ,  523  provide a connection to one or more external delivery systems provided in a diagnostic device, such as card reader  10 , as discussed further below. The channel  560  is fluidly connected to the connection port  522 , and the channel  562  is fluidly connected to the connection port  523 . 
     The optical sensing or assay region  576  provides another sensing functionality to a diagnostic consumable incorporating the substrate  500 . The channel  542  fluidly connects the channel  540  to the sample preparation channel  102  through via  112 . In the embodiment shown, the sample preparation channel acts as a haemolysis channel  102  to haemolyse a blood sample before it reaches optical sensing region  576 . Thus, channel  102  is fluidly connected to a chamber  110  within the optical sensing region  576 . The channel  541  fluidly connects the chamber  110  and the waste fluid reservoir  543  through via  545 . The channel  562  fluidly connects the waste fluid reservoir  543  to port  523  through via  545 . In operation, at least a portion of a fluid sample, such as a blood sample, could be directed through the channel  542 , the fluid preparation channel  102  and into the chamber  110  to be optically analyzed in the optical sensing region  576 . 
       FIGS. 7 and 8  illustrate plan views of an example diagnostic consumable  600  that incorporates the substrate  500  shown in  FIGS. 3 to 6 . The diagnostic consumable  600  could be considered an assembled diagnostic card or test card for blood analysis and/or testing. In some implementations, the diagnostic consumable  600  is a microfluidic device. The diagnostic consumable  600  could be configured, by being sized and shaped for example, to be received by a diagnostic device, such as card reader  10 .  FIG. 7  is a view of the top surface  602  of the diagnostic consumable  600 , and  FIG. 8  is a view of the bottom surface  604  of the diagnostic consumable. In addition to the substrate  500 , the device  600  includes the cover layer  130  covering a fluid preparation state  100 , such as a haemolysis stage, top cover layer  606 , a bottom cover layer  608 , a sensor array  610 , a calibration fluid pack  612  (illustrated using parallel hatching) and a valve  614  (illustrated using cross-hatching). Many components of the substrate  500  are not labelled in  FIGS. 7 and 8  for the purpose of clarity. 
     At least a portion of the top surface  502  and bottom surface  504  of the substrate  500  are sealed using the top cover layer  606  and the bottom cover layer  608 , respectively. The top and bottom cover layers  606 ,  608  could be impermeable to liquids (and possibly gases) to provide a liquid tight (and possibly gas tight) seal. In some implementations, the top and bottom cover layers  606 ,  608  could include plastic, metal and/or ceramic films that are bonded to the substrate  500  using an adhesive. For example, in some implementations, the top cover layer  606  and/or the bottom cover layer  608  could be implemented as an adhesive label or sticker. Non-limiting examples of adhesives include acrylic adhesives and silica adhesives. The top and bottom cover layers  606 ,  608  could form a seal around one or more components of the substrate  600 . For example, the top cover layer  606  could seal, at least in part, the sample fluid reservoir  508 , the bubble traps  514 ,  516 , the sensing region  518 , the waste fluid reservoir  520  and the channels  540 ,  541 ,  542 ,  548 ,  552 ,  558 . The bottom cover layer  608  could seal, at least in part, the sample input port  506 , the calibration fluid reservoir  510 , the bubble traps  514 ,  516  and the channels  538 ,  544 ,  546 ,  550 ,  554 ,  556 ,  560 ,  562 . The top cover layer  606  is illustrated as being substantially transparent and the bottom cover layer  608  is illustrated as being substantially opaque, but this is only an example. In general, either or both of the top cover layer  606  and the bottom cover layer  608  could be transparent, translucent, opaque, or a combination thereof. In  FIG. 7 , dashed lines are used to illustrate components that are under the top cover layer  606 . 
     In this example, the sensor array  610 , which could also be referred to as an electrode module, is bonded to the bottom surface  504  of the substrate  500 . The sensor array  610  overlaps and seals at least a portion of the sensing region  518 . The bottom cover layer  608  does not overlap the sensor array  610 . The sensor array  610  could be fabricated using smart-card chip-module technology. In this example, the sensor array  610  includes a gold coated copper metal foil laminated to an epoxy foil element  616  with an optional adhesive. The metal foil is formed into an array of electrode elements  618 . Each electrode element  618  could have a connection end for forming an electrical connection to a measuring circuit in a card reader module, for example. The connection ends of the electrode elements  618  are not labelled for reasons of clarity. Multiple sensors  620  are coupled to the electrode elements  618 . Each of the sensors  620  are positioned over the sensing region  518  of the substrate  500 . In use, the sensors  620  could be used to measure one or more properties of a calibration fluid and/or sample fluid in the sensing region  518 . The sensors  620  could be electrochemical sensors that are used for measuring concentrations of gases, electrolytes and/or metabolites. The sensors  620  could include potentiometric sensors to measure sodium, potassium, ionized calcium, chloride, urea, TCO 2 , pH levels and/or CO 2  partial pressure; amperometric sensors to measure O 2  partial pressure, glucose, creatinine and/or lactate; and/or conductometric sensors to measure hematocrit, for example. The number and geometry of the electrodes  618  and the sensors  620  is provided by way of example only. The same module fabrication technology can be used to make sensor arrays with many different electrode/sensor numbers and geometries. 
     The calibration fluid pack  612  is sandwiched between the calibration fluid pack region  578  of the substrate  500  and the bottom cover layer  608 . The calibration fluid pack  612  could fill the calibration fluid reservoir  510  and the channel  550 . The calibration fluid pack  612  could be provided to seal and store a calibration fluid, in order to improve the stability of the calibration fluid over time. For example, the calibration fluid pack  612  could inhibit gases, such as carbon dioxide, from permeating into and/or out of the calibration fluid. 
     The top surface  502  of the substrate  500  is substantially sealed by the top cover layer  606 , with the exception of a hole  622  that corresponds to the location of the sample input port  506 . The hole  522  allows a blood sample delivery device, such as a syringe or capillary tube, to be coupled to the sample input port  506  to deliver a blood sample into the diagnostic consumable  600 . In addition, the top cover layer  606  also includes a second hole  633  that corresponds to the location of the optical sensing region  576 . As discussed earlier, the sample input port  506  may include a gasket component that facilitates a sealing engagement between the sample input port  506  and the sample delivery device. For example, the gasket component may be a rubber or silicone component installed in the sample input port  506  and sized and shaped to sealingly engage a sample delivery device. 
     The bottom surface  504  of the substrate  500  is substantially covered by the bottom cover layer  608 , with the exception that the sensor array  610  and the via  524  are not sealed by the bottom cover layer. The bottom cover layer  608  includes cuts or scoring  624 ,  626 . The scoring  624 ,  626  could be provided to render the bottom cover layer  608  more malleable and workable in the area proximate the scoring. The position of the scoring  624  corresponds to the position of the valve  614 . The scoring  624  could make the portion of the bottom cover layer  608  that is adjacent to the valve  614  more flexible, and could therefore permit the valve to be manipulated more easily. The position of the scoring  626  corresponds to the position of the calibration fluid reservoir  510 . The scoring  626  could make the portion of the bottom cover layer  608  adjacent to the calibration fluid reservoir  510  more flexible, and therefore permit the calibration fluid pack  612  to be manipulated more easily. 
     The bottom cover layer  608  also includes holes  628 ,  630  corresponding to the location of the delivery system connection ports  522 ,  523  on the substrate  500 . The connection ports  522 ,  523  could be connected to a delivery system in a diagnostic device, such as the card reader  10 , through the holes  628 ,  630 . The holes  628 ,  630  could be sized and shaped to form a seal between the delivery system and the connection ports  522 ,  523 . 
     The bottom cover layer  608  includes a hole  632  corresponding to the optical sensing region  176  and generally aligned with the hole  633  in the top cover layer  606 . The holes  632 ,  633  and the transparency of the substrate  500  and the cover layer  130  in the area of the optical sensing region  576  facilitate optical sensing within the optical sensing region. 
     In this example, a 1D barcode  634  is printed on the bottom cover layer  608 . The barcode  634  could be read by a diagnostic device, such as the card reader  10 , when the diagnostic consumable  600  is inserted into the card reader  10 . The barcode  634  could authenticate the diagnostic consumable  600  and/or provide information regarding the diagnostic consumable. For example, the barcode  634  could indicate the date that the diagnostic consumable  600  was manufactured. The barcode  634  is one example of a machine-readable code that could be present on the bottom cover layer  608  or elsewhere on the diagnostic consumable. Other examples of machine-readable codes include 2D barcodes. Radio-frequency identification (RFID) chips or tags could also or instead be used. 
     Referring to  FIGS. 9 to 21 , embodiments of a delivery system will now be described. As discussed above, the delivery system may be configured and arranged in a diagnostic device, such as the reader  10 , to operatively connect to the diagnostic consumable  600  for delivering a fluid sample through a channel of the diagnostic consumable. Thus, for example, a fluid sample, such as a blood sample, may be delivered to a desired or predetermined location in the diagnostic consumable  600 , for example sensing region  518  and/or optical sensing region  576 . 
     The delivery system will be described primarily in terms of a vacuum pressure delivery system, meaning that the fluid sample is delivered through the channel of the diagnostic consumable via the application of vacuum pressure pulses downstream of the fluid sample. However, the principles of the present disclosure include and may also be applied to delivery systems and methods for delivering the fluid sample using positive pressure pulses, meaning that the fluid sample is delivered through the channel of the diagnostic consumable via the application of positive pressure pulses upstream of the fluid sample. 
     As shown schematically in  FIG. 9 , in some embodiments, the delivery system  200  includes a vacuum source  202 , a charge vessel  204  fluidly connected to the vacuum source  202  upstream of the vacuum source  202 , a first valve  206   1  immediately upstream of the charge vessel  204 , and a second valve  206   2  immediately downstream of the charge vessel  204 . The delivery system  200  is in turn fluidly connected downstream of the diagnostic consumable  600 . The components of the delivery system  200  are fluidly connected to each other in any manner suitable for that purpose. 
     It is noted that the terms “upstream” and “downstream” are relative terms chosen with respect to the travel direction of the fluid sample through the channel. “Downstream” is considered to be in the direction of travel of the fluid sample, while “upstream” is considered to be against the direction of travel of the fluid sample. However, the use of “upstream” and “downstream” can be reversed without departing from the principles of the present disclosure. Similarly, the terms may be reversed when considering embodiments where the delivery system is connected to the channel upstream of the fluid sample and positive pressure pulses are applied. 
     The first and second valves  206   1 ,  206   2  are operable to open and close at a predetermined frequency to alternatively charge and discharge the charge vessel  204 , thereby applying vacuum pressure pulses to a channel of the diagnostic consumable  600 . 
     In particular, in each cycle, the second valve  206   2  opens while the first valve  206   1  remains closed, thereby fluidly connecting the charge vessel  204  to the vacuum source  202 . The charge vessel  204  is thereby pressurized to the vacuum pressure of the vacuum source  202 . The second valve  206   2  then closes and the first valve  206   1  opens, fluidly connecting the charge vessel  204  with the channel of the diagnostic consumable that initially contains air at ambient pressure downstream of the fluid sample. In effect, the pressurized charge vessel  204  acts to generate a vacuum downstream of the fluid sample. The vacuum pressure is thereby applied to the channel. However, notably, the vacuum pressure is not constant, since the first valve  206   1  closes and the second valve  206   2  opens to repeat the cycle. Additionally, in-between cycles, movement of the sample causes the vacuum to decay ( FIG. 11B ). In this manner, the delivery system  200  applies vacuum pressure pulses to the channel of the diagnostic consumable  600 . The work being done by the pressure pulses is a function of the pressure of the pressure pulses and the volume of the charge vessel  204 . As noted above, it will be understood that the system of  FIG. 9  may also be used to deliver the sample using positive pressure pulses. 
     Referring to  FIG. 10 , according to embodiments of the present disclosure, a range of delivery times can be relatively narrow: comparable to a delivery system at the same source pressure but without a charge vessel, without necessitating very fast delivery for low-viscosity samples (where stopping the sample accurately can be difficult at high speed). 
     In delivery systems with a charge vessel, increasing the magnitude of the source vessel pressure while keeping the discharge frequency of the charge vessel constant, reduces the range of delivery times (and vice versa), as does increasing the magnitude of pressure of a constant-pressure source. This is indicated by the arrow labelled “Higher Pressure” showing a reduced slope from dotted line to solid line. 
     However, unlike the constant-pressure source, the range of delivery times may be translated up or down by changing a switching (i.e. discharge) frequency of the charge vessel. This is indicated by the arrows labelled “Lower Frequency” and “Higher Frequency” showing the translation of the dotted line up or down to parallel solid lines. Again, this may prevent undesirably fast delivery. Depending on the fluid sample to be delivered, a user might predetermine the combination of pressure and charge vessel cycle frequency to also prevent undesirably slow delivery. 
     Referring to  FIG. 11A , one example is shown. In this example, a delivery system with the following pumping variables were used:
         10 mL volume for vacuum source, set to initial pressure of −100 mbar (i.e. sample pulled by vacuum pressure)   100 μL volume for charge vessel   10 Hz frequency cycle for charging and discharging charge vessel   Samples of 10 and 80 Haematocrit (Hct), which correlates with viscosity, were delivered the same distance   Pressure measured in the volume between charge vessel and sample       

     As can be seen by the plots of pressure vs. delivery time, the average driving pressure increases in magnitude with the more viscous sample (to −5 mbar for 80 Hct vs. −2 mbar for 10 Hct). This effect, discussed below in reference to  FIG. 11B , aids in reducing the range of delivery times, i.e. more viscous samples experience more driving pressure than less viscous samples. 
     Referring to  FIG. 11B , it can be seen that between charge vessel transients, the change in pressure is related to the change in volume between the charge vessel and the fluid sample front (i.e. the volume in which the pressure is being measured). 
     According to the ideal gas law, an increase in pressure is proportional to a volume decrease, and vice versa. Thus, as can be seen, ΔP 10Hct  is almost double ΔP 80Hct . Accordingly, between pressure pulses from the charge vessel, the 10 Hct sample moves almost twice as far as the 80 Hct sample. While this may not be the case of every pressure pulse, it is the case for most, particularly for the time range shown in  FIG. 11B . 
     Thus, a consequence of the smaller pressure increase for the more viscous sample is that the average driving pressure increases in magnitude over time of sample delivery. The magnitude of driving pressure for all samples will also increase through points of higher resistance, and as larger volumes of sample are delivered, increasing drag. 
     Moreover, if the channel geometry within the consumable remains constant, the total decrease in volume between the charge vessel and sample fluid front (i.e. the volume traversed by the sample fluid front) may be estimated at any point by summing the pressure differences, ΔP, between all previous charge vessel transients. For example, the volume traversed by the 10 Hct sample from beginning to end of sample delivery may be estimated as: Volume traversed 10Hct =Σ (ΔP 10Hct ). This is true for all samples, from the least to most viscous (for example, water to 80 Hct blood). As both samples shown  FIGS. 11A and 11B  were delivered to the same point in the consumable, Σ (ΔP 10Hct )=E (ΔP 80Hct ) for the entirety of each respective pressure trace (see  FIG. 11C ). The sample fluid flow front may be monitored, and stopped at a location of choice, by knowing the association between distance travelled and volume traversed for the consumable of interest. 
     Accordingly, in general, repeated application of pressure pulses pressurizes the channel of the fluid sample incrementally in steps or bursts as compared to a constantly applied pressure. Doing so counters the effect of viscous drag experienced by the fluid sample in the channel, as seen in  FIG. 11A . 
     Furthermore, summing the pressure changes due to sample movement (e.g. Σ(ΔP 10Hct ) as shown in  FIG. 11B ) at any point during sample delivery (i.e. along the 10 Hct trace in  FIG. 11A ) allows one to determine the relative position of the sample flow front at that point, as the pressure change is due to sample movement. This may allow the delivery system to be used to deliver a sample to a particular location along a channel without sensors for direct detection of the fluid flow front. 
     For example, as seen in  FIG. 11C , two samples (10 Hct and 80 Hct) were moved through a channel, starting and stopping at the same point. The pressure signals used were those shown in  FIG. 11B . The positions were calculated and controlled using the summation of pressure increases. 
     Moreover, to deliver samples of different viscosity to a predetermined location, such as the sensing region  518 , at approximately the same time without changing the vacuum source pressure, one could alter the discharge frequency of the charge vessel during delivery—reducing it for less-viscous samples and increasing it for more-viscous ones—based on an initial viscosity estimate or a measurement of the time elapsed vs distance travelled in the channel (calculated as above). 
       FIG. 12  shows a plot of experimental data comparing delivery of blood samples to sensing region  518  of the consumable discussed above using an embodiment of a delivery system  200  according to the present disclosure (dotted line) and a constant pressure system (solid line). The delivery system according to embodiments of the present disclosure used a 100 μL charge vessel set to a discharge frequency of 10 Hz and a 10 mL source vessel set to 150 mbar pressure. The plot shows time of delivery of the blood sample to sensing region  518  as a function of the blood sample haematocrit (Hct). As discussed above, when the pressure acting on the sample is incrementally increased by charging and discharging the charge vessel, the sample delivery time is less dependent on viscosity (or haematocrit) compared to a constant-pressure system (solid line). Here the range of delivery times is reduced by approximately 80%. Moreover, the delivery times vary approximately linearly across the range of sample viscosities (it may be exactly linear with respect to viscosity, as shown in  FIG. 10B , and approximately linear with respect to Hct as Hct is not linearly related to viscosity), simplifying any delivery-time compensation in measured analyte concentrations that may be performed by a processor of the diagnostic device evaluating signals produced by, for example, the sensor array  610 . It may also be beneficial that the low-viscosity samples, which in some implementations are aqueous quality-control solutions, are effectively slowed by the delivery system  200 , since overly-rapid sample delivery can cause a number of problems including undesirable bubble formation and wasting of sample due to assay region overshoot, resulting from time-lag in stopping sample (by venting to atmosphere). 
     While the above-noted advantages of embodiments according to the present disclosure may be achieved with a variety of volumes chosen for the source and charge vessels, the source vessel should be relatively large in volume relative to the volume between the charge vessel and the sample front. If the source vessel volume is insufficiently large, the driving pressure may decay to a point where sample delivery is unacceptably slow. 
       FIG. 13  is a schematic diagram showing another embodiment of a delivery system  200  according to the present disclosure. The delivery system  200  includes a vacuum pump  208  as the vacuum source and a source vessel  210  fluidly connected to the vacuum pump  208  and charge vessel  204  between the vacuum pump  208  and the charge vessel  204 . 
     In the illustrated embodiment, the source vessel  210  acts as an intermediary source of vacuum pressure and is pressurized by the vacuum pump. Once the desired vacuum pressure is reached, as measured by a pressure gauge  212   1 , the source vessel  210  is fluidly connected to the charge vessel  204  to pressurize the charge vessel  204 . In some embodiments, the source vessel  210  has a volume larger than a volume of the charge vessel  204 . For example, the source vessel  210  may have a volume of 10 mL and the charge vessel  204  a volume of 100 μL. However, the source vessel  210  and charge vessel  204  may be dimensioned differently. In particular, the charge vessel  204  may be dimensioned in dependence on the viscosity range of the fluid samples to be delivered. 
     Third and fourth valves  206   3 ,  206   4  are operable to control the pressurizing of the source vessel  210 . When the source vessel  210  is to be pressurized by the vacuum pump, the third valve  206   3  is in an unactuated state while the fourth valve  206   4  is actuated. The second valve  206   2  remains closed. Vacuum pump  208  may be a DC-powered pump (e.g. a diaphragm pump or peristaltic pump). In some embodiments, vacuum pump  208  may be a piezoelectric pump, which can typically operate at voltages higher than a DC-powered pump. The pump  208  may generate a vacuum pressure above that which is intended for source vessel  210 . Accordingly, the source vessel  210  is pressurized until only a desired vacuum pressure is reached, as measured by the first gauge  212   1 . The third valve  206   3  remains unactuated once the desired vacuum pressure is reached in the source vessel  210 . When unactuated, the fourth valve  206   4  remains closed to isolate the vacuum pump  208  from the remainder of the delivery system  200  and, in particular, the source vessel  210 . In the event that the source vessel  210  was pressurized to a greater extent than intended or desired, the third valve  206   3  is actuated to be temporarily opened to the atmosphere and “bleed” air until the source vessel  210  is returned to the desired pressure set point. 
     Charging and discharging of the charge vessel  204  may occur as follows: Once the source vessel  210  is at the desired vacuum pressure, the second valve  206   2  is opened to charge the charge vessel  204 . The second valve  206   2  is then closed. Next, the first valve  206   1  is opened to expose the channel of the consumable to the incremental pressure charge (i.e. pulse) of the charge vessel  204 . The first valve  206   1  is then closed, followed by an opening of the second valve  206   2  to recharge the charge vessel  204 . These steps are repeated to charge and discharge the charge vessel  204  at the predetermined frequency. 
     In some embodiments, the charge vessel  204  may be either or both partially charged and discharged if the first and second vales  206   1  and  206   2  are switched fast enough. This may add another degree of freedom of control beyond merely increasing the source pressure, altering the source and charge vessel volumes, and altering the discharge frequency. 
     The illustrated embodiment of the delivery system  200  also includes fifth and sixth valves  206   5 ,  206   6 . The fifth valve  206   5  acts as a bypass valve and is opened to atmosphere if it is desired to stop motion of the fluid sample. Otherwise, the fifth valve  206   5  allows the vacuum pressures pulses to pass through. The sixth valve  206   6  acts as a selection valve and allows the delivery system to selectively apply the pressure pulses to a desired channel of the diagnostic consumable (connected to either of the ports  302   4  or  302   5 ). Thus, as will be discussed below, if the delivery system is fluidly connected to ports  522 ,  523 , the sixth valve may be used to direct the vacuum pressure pulses into one of these two ports, thereby moving a fluid through channels leading to sensing region  518  (i.e. the BGEM sensor) or to the optical sensing region  576  (e.g. the COOX sensor). 
     A second pressure gauge  212   2  may be used to track pressure in the channel of the diagnostic consumable  600 , which may aid in the above-described pressure-feedback fluid delivery and position prediction. 
     Components of the delivery system  200 , including the charge vessel  204 , and the first, second, fifth and sixth valves  206   1 ,  206   2 ,  206   5  and  206   6  may be connected to and/or embodied in a manifold  300 . The presence of a manifold  300  may aid in manufacturing and/or assembly of the delivery system  200 , as well as arranging the components in the reader  10  in a manner that is both space and energy efficient. 
     In the illustrated embodiment, the manifold  300  includes a first manifold port  302   1  that fluidly connects the manifold to the remainder of the delivery system  200 , a second manifold port  302   2  that fluidly connects the manifold to the second pressure gauge  212   2 , a third port  302   3  open to atmosphere, a fourth port  302   4  to connect to sensing region  518  (i.e. the BGEM sensor) of the consumable, and a fifth port  302   5  to connect to a the optical sensing region  576  (i.e. the COOX sensor) of the consumable, both of which will be discussed further below. 
       FIG. 14  shows components of the delivery system  200  as per the embodiment shown schematically in  FIG. 13 . The components are shown in isolation and not necessarily in the relative arrangement they would be in when incorporated into the reader  10 . The vacuum source  208  shown in the illustrated embodiment is an off-the-shelf diaphragm pump. In the illustrated embodiment, the vacuum source  208 , such as the diaphragm pump, need not be precisely controlled or need not be a source capable of producing a wide, yet precise, spectrum of vacuum pressures because the vacuum source  208  is used to pressurize the source vessel  210 , which is in turn set to a precise vacuum pressure by measuring pressure at the first gauge  212   1  and cycling the third valve  206   3 . 
     The illustrated shape of the components in  FIG. 14  is exemplary only. For example, the source vessel  210  may be shaped as desired or required in order to fit compactly around other components of the reader  10 , while still maintaining the desired volume (e.g. 10 mL in one embodiment). Furthermore, while first, second, fifth and sixth valves  206   1 ,  206   2 ,  206   5 ,  206   6  are mounted onto the manifold  300 , third and fourth valves  206   3 ,  206   4  are shown as mounted onto a mounting bracket  214  that may be mounted within the reader  10 . Fluid connections between components of the delivery system  200  are established with tubing  216 . 
     As shown schematically in  FIG. 15 , in some embodiments, the card reader  10  includes a controller  400 . The controller may be operatively connected to one or more of the vacuum source  208 , each of the valves  206 , and each of the pressure gauges  212  in order to control these components of the delivery system  200 . For example, the controller  400  may act as a vacuum controller configured to open and close the first and second valves  206   1 ,  206   2  at the predetermined frequency. Similarly, the vacuum controller may be configured to vary the predetermined frequency of the vacuum pressure pulses in dependence on the viscosity of the fluid sample, as discussed above, to aid in ensuring that samples with different viscosity travel substantially the same distance through the channel in substantially the same time. The vacuum controller may also be configured to control the vacuum pressure provided by the vacuum source  208 , such as the vacuum pump. 
     The controller may be a logic controller or processing unit such as Programmable Logic Controller (PLC) or other control device, whether electronic and/or mechanical, that achieves the desired functionality. The controller  400  may be pre-programmed and/or receive instructions from a processing unit, such as a central processing unit (CPU), embedded in the reader  10 . Alternatively, or in addition, the controller may receive instructions from an external control device, such as a mobile device, that is used to operate the reader  10  and, in some embodiments, also display the output of the diagnostic. 
     The valves used in the delivery system  200  may be of any suitable type. In some embodiments, the valves are solenoid-type valves with opening/closing times on the order of &lt;5 milliseconds. 
     As discussed above, the diagnostic consumable  600  may be inserted into reader  10  in order to run a diagnostic test on a fluid sample. Upon insertion, the delivery system  200  is operatively connected to the diagnostic consumable  600  to deliver the fluid sample that will be or has been provided through, for example, the input port  506 . 
       FIGS. 16 to 18  show top, side and bottom views, respectively, of the diagnostic consumable  600  in relation to the manifold  300  of the delivery system  200  after insertion of the diagnostic consumable  600  into the reader  10 . For the sake of clarity, the diagnostic consumable  600  and the manifold  300  are shown in isolation, without other components of the reader  10 . Moreover, not all components of the diagnostic consumable  600  are labelled and the diagnostic consumable  600  is shown without the top cover layer  606  in  FIG. 16 . 
     The reader  10  may include stops (not shown) to limit the travel and extent to which the diagnostic consumable may be inserted into the opening  12 . Thus, upon complete insertion, the diagnostic card  600  is appropriately positioned so as to be operably connectable, with components of the reader  10 , including the delivery system  200  and, in the illustrated embodiment, the manifold  300 , via the ports of the manifold. 
     In the illustrated embodiment, upon complete insertion, the diagnostic consumable  600  is positioned with respect to the manifold  300  such that connection structures, for example rubber gaskets  304 ,  306 , are aligned with holes  630 , 628 , respectively, of the diagnostic consumable  600  and thus connection ports  523 ,  522 , respectively, in turn connecting to the fourth and fifth ports  302   4  and  302   5 . Rubber gaskets  304 ,  306 , include central apertures that are surrounded by resilient rubber and, in operation, fluidly connect to ports,  523 ,  522 . Upon complete insertion of the diagnostic consumable  600  into the opening  12 , the manifold  300  is raised to press the rubber gaskets  304 ,  306  firmly against bottom surface  604  in order to create an air-tight seal. A back stop  22 , which is shown schematically, may be present in the reader  10  and positioned above the diagnostic consumable  600  to counteract the force applied by pressing the rubber gaskets  304 ,  306 , against the diagnostic consumable  600  further aiding to create the air-tight seal. 
       FIG. 19  shows a bottom surface  308  of the manifold  300  without the first, second, fifth and sixth valves  206   1 ,  206   2 ,  206   5 ,  206   6 , which may be collectively referred to as the manifold valves. The manifold  300  includes three port recesses  310   a ,  310   b , and  310   c  for each of the manifold valves, as well as valve mounting holes  312  positioned such that one mounting hole  312  is positioned on either side of each manifold valve. For the sake of clarity, only the port recesses and valve mounting holes for the sixth valve are labeled. 
     Each of the manifold valves is mounted using pins, bolts, screws or other mounting means inserted through the mounting holes  312 . Each of the manifold valves has three ports, which are face-sealed to the manifold  300  in fluid communication with respective port recesses  310   a ,  310   b , and  310   c . As can be seen, not every port recess has a through hole. For example, the port recess  310   a  for the fifth valve  206   5  does not. Where a port recess does not have a through hole, the port is intentionally blocked to close the path through the respective port of the valve. 
     Shown in dashed lines are first and second tubing holes  316   1 ,  316   2 , respectively, used to connect first and second manifold ports  302   1 ,  302   2 . 
     The manifold  300  also includes four through holes  314  for mounting the manifold  300  internally in the reader  10 . 
       FIGS. 20 and 21  show a top surface  318  of the manifold  300 . Fluid communication between the manifold valves and charge vessel  210  are achieved via air lines, such as channels  320  (or plumbing grooves) provided in or on the manifold  300 . In the illustrated embodiment, the channels  320  have been formed or machined into the top surface  318 . However, in some embodiments, the manifold  300  may be moulded, such as injection moulded, with the air lines provided by tunnels or spaces formed inside the manifold. The manifold  300  could also be made, among other ways, from two pieces of metal/plastic sealed together with a sealing element such as a large o-ring and clamped together with screws. 
     Where port recesses  310   a ,  310   b ,  310   c  are through holes, they fluidly connect the respective valve ports to the channels  320 . 
     When the air lines are formed as channels, a label  322  may be applied to the top surface  318  to seal channels that are not intended to be open to atmospheric pressure. Holes  324   a  and  324   b  are provided in the label  322  for fluidly connecting the channels  320  to the central apertures of the rubber gaskets  304 ,  306  and thus fluidly connecting the channels  320  to connection ports  522 ,  523 . The rubber gaskets  304 ,  306 , are in turn mounted on the manifold  300  above label  322 . Thus, holes  324   a  and  324   b  act as the fourth and fifth ports  302   4  and  302   5 , discussed above, for connecting the manifold to corresponding testing array portions of the consumable. Atmosphere channel  320   a  runs outside the label  322  to atmospheric pressure within the reader  10  for venting the fifth valve  206   5 , thereby acting as the third port  302   3  discussed above. 
     In the illustrated embodiment, charge vessel  210  is formed by a charge vessel channel  320   b  and is fluidly connected to the first and second valves  206   1 ,  206   2  via connection channels  320   c  and  320   d , respectively. The dimensions of charge vessel  320   b  may been chosen to obtain a desired volume, for example 10 μL but a variety of dimensions and shapes may be used depending on the desired volume, configuration of the manifold and/or configuration of the reader  10 . 
     It is also to be understood that any or all of the components shown as embodied in the manifold  300  may be embodied as separate components and fluid connections between components may be embodied in other ways, such as using tubing. 
     Referring to  FIG. 22 , embodiments of methods according to the present disclosure will be described.  FIG. 22  shows a flow diagram of a method  700  according to one embodiment of the present disclosure for delivering a fluid sample through a channel of a diagnostic consumable, such as the diagnostic consumable  600 . The method  700  includes steps  702 ,  704  and  706 . 
     Step  702  includes receiving the diagnostic consumable in a reader comprising a delivery system. For example, in some embodiments, this includes inserting the diagnostic consumable  600  into reader opening  12  of the reader  10  that comprises the delivery system  200 . 
     Step  704  includes operatively connecting the delivery system to the channel. For example, in some embodiments, such as embodiments where the delivery system operates with vacuum pressure pulses, this includes pressing the manifold  300  against the diagnostic consumable  600  so that rubber gaskets  304 ,  306  form an air-tight seal between the fourth and fifth ports  302   4 ,  302   5  and connection ports  522 ,  523 , respectively. 
     For positive pressure pulses this step could include pressing the manifold against input  506  to create an air tight seal. 
     Step  706  includes applying pressure pulses to the channel at a predetermined frequency. For example, in some embodiments, this includes step-wise ramping up the vacuum driving pressure downstream of the fluid sample. In other embodiments, this may include step-wise ramping up the driving pressure upstream of the fluid sample. 
     In some embodiments, step  706  includes pressurizing a charging vessel to a predetermined pressure (e.g. vacuum pressure) and fluidly connecting the pressurized charging vessel to the channel. For example, in some embodiments, this includes cycling the first and second valves  206   1 ,  206   2  at a predetermined frequency so that charge vessel  204  is alternatingly pressurized and opened to the channel of the diagnostic consumable  600 , thereby step wise ramping up the pressure in the channel. In some embodiments, the frequency of the pressure pulses may be predetermined in dependence on the viscosity or a viscosity range of the fluid samples to be delivered through the channel. 
     In some embodiments, step  706  includes pressurizing a source vessel operably connected to the charging vessel and using the source vessel to pressurize the charging vessel, wherein a volume of the source vessel is larger than a volume of the charge vessel. For example, in some embodiments, this includes pressurizing source vessel  210  downstream of the charge vessel  204  fluidly connecting the source vessel  210  to the charge vessel  204 , such as by opening the second valve  206   2  and closing the first valve  206   1 , thus using the source vessel  210  to pressurize the charging vessel  204 . 
     Moreover, in some embodiments, step  706  may include using a pressure source to pressurize the source vessel. For example, in some embodiments, this includes using vacuum pump  208  downstream of the source vessel  210  to pressurize the source vessel by opening the third valve  206   3  and, if present, the fourth valve  206   4 , while the second valve  206   2  remains closed. 
     In some embodiments, the method  700  further includes adjusting the predetermined frequency in dependence on the speed of travel of the fluid sample within the channel. For example, in some embodiments, this includes using controller  400  to change the rate of cycling of the first and second valves  206   1 ,  206   2  in order to generate a frequency of pressure pulses adapted to the speed of travel of the fluid sample as measured. 
     The example operations of the method  700  are illustrative of example embodiments. Various ways to perform the illustrated operations, as well as examples of other operations that may be performed, are described herein. Further variations may be or become apparent. 
     The embodiments of the system and method for delivering a fluid sample through a channel of the diagnostic consumable have been described with reference to a vacuum pressure pulses. However, as discussed above, in some embodiments according to the present disclosure, the pressure pulses may be obtained by generating positive pressure pulses upstream of the fluid sample to “push” the sample through the channel rather than “pull” it through the channel. Accordingly, discussion of principles and implementations of the present disclosure with reference to “vacuum” pressure could be suitably modified to be applied to systems and methods using positive pressure pulses upstream of the fluid sample. 
     In such embodiments, for example, the delivery system would be operatively connected to the channel upstream of the fluid sample and pressurize a charge vessel at a predetermined frequency with overpressure, which would be opened to the channel. The overpressure behind the fluid sample would force the sample through the channel. The periodic pressure pulses would step-wise ramp up the pressure upstream of the fluid sample. It will be understood that many of the components of the delivery system  200 , such as the valves, gauges, source vessel, pump and charge vessel could be used in a positive pressure system that instead creates an overpressure instead of vacuum pressure. 
     For example, in one embodiment of a delivery system using positive pressure, after sample injection one could seal against input  506  and close, or seal shut, vent  524 . Otherwise the sample would be pushed out vent  524 . In such embodiments, one could only deliver sample from input  506  to via  528 . Alternatively, in some embodiments, one could close input  506  and seal against vent  524 . Positive pressures would then be applied. In such an embodiment, one could move/deliver all sample between via  528  and vent  524 . 
     Although the present disclosure relates primarily to delivery systems and methods for delivering a fluid sample, such as a blood sample, through a channel of a diagnostic consumable, the embodiments described herein could also be used in other fluidic devices where a fluid sample is being delivered to a predetermined location within the fluidic device.