Method and system for determining plasma protein content of whole blood using refractometry

Abstract

A method and system are provided for measuring plasma protein levels in whole blood while a plasma donor is connected to an apheresis machine. A refractometer associated with the apheresis machine is capable of receiving a portion of a disposable tubing set including an integrated cuvette and a prism. The integrated cuvette of the disposable tubing set is inserted into a receiving space of the refractometer associated with the apheresis machine such that a light source and a sensor are precisely aligned and oriented with respect to a sensing surface of the prism and the integrated cuvette. Calibration of the refractometer is performed using an anticoagulant pumped through the disposable tubing set including the integrated cuvette and prism. Based on the light intensity associated with this calibration, the whole blood is measured to determine plasma protein levels and donor eligibility.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims priority to U.S. Patent Application No. 17 / 963,527, filed October 11, 2022, which claims the benefit of U.S. Provisional Patent Application No. 63 / 271,033, filed October 22, 2021. The entire disclosure of the above application is incorporated herein by reference.

[0002] The present disclosure relates generally to refractive index measurements, and particularly during apheresis. Plasma protein content of whole blood The present invention relates to a method and system for determining [Background technology]

[0003] Apheresis is a method of extracting whole blood from a donor while the donor is connected to a specialized device. The extracted whole blood is sent via various tubing to a separator in the device, which separates the whole blood into one or more components or components. These components may include plasma, red blood cells, white blood cells, and platelets. During apheresis, the plasma (and / or other desired blood components) is separated from the other blood components in the whole blood and then collected in a bag or bottle (e.g., for later use in a therapeutic setting or for treatment, transfusion, etc.). The other blood components are then returned to the donor during the apheresis process. The donor is connected to the apheresis device during the separation and collection of one or more blood components.

[0004] According to the U.S. Food and Drug Administration (FDA), a plasma donor must have a plasma protein concentration (level) of 6.0 g / dL or greater and 9.0 g / dL or less to be eligible to donate plasma. See, e.g., 21 C.F.R. §630.15(b)(4). Traditionally, plasma protein levels of potential plasma donors have been measured by collecting a blood sample from the potential plasma donor via a painful finger prick, injecting the blood from the finger prick into a capillary tube, centrifuging the capillary tube and blood, and placing a drop of plasma from the capillary tube into a handheld refractometer. The refractometer can evaluate the sample and determine its plasma protein level. If the plasma protein level of the sample is within an acceptable range (e.g., 6.0 g / dL to 9.0 g / dL), the potential plasma donor is permitted to donate plasma. However, if the plasma protein level of the sample is outside the acceptable range (eg, below 6.0 g / dL or above 9.0 g / dL), the potential plasma donor will not be permitted to donate plasma. Summary of the Invention [Problem to be solved by the invention]

[0005] It is estimated that less than approximately 1.5% of potential plasma donors are ineligible to donate plasma due to insufficient plasma protein level measurements. However, all donors are required to undergo plasma protein level testing to determine their eligibility. This ultimately results in all potential plasma donors undergoing a painful finger prick before donating plasma. Notably, finger pricks cause residual pain at the site of the finger prick (usually on the sensitive ball of one or more fingers) for hours, days, or longer. The present disclosure advantageously eliminates the need for finger pricks. Furthermore, this manual, conventional process (e.g., obtaining a sample, centrifuging the sample, placing the sample in a handheld refractometer, etc.) is time-consuming, complicated, and prone to error. It also requires the use of personal protective equipment (PPE) and is an undesirable open blood event that poses potential risks to the operator. [Means for solving the problem]

[0006] The embodiments presented herein address these and other problems. The present disclosure provides methods and systems for measuring plasma protein levels while a donor or patient is connected to an apheresis machine or other extracorporeal blood processing device (e.g., via a needle or cannula and tubing set, etc.). In one example, the system includes a refractometer associated with the apheresis machine. The refractometer can receive a portion of a disposable tubing set that includes an integrated cuvette and prism. The integrated cuvette of the disposable tubing set is inserted into a receiving space of the refractometer associated with the apheresis machine such that a light source (e.g., a light-emitting diode (LED), laser, etc.) and a sensor (e.g., a charge-coupled device (CCD), complementary metal-oxide semiconductor (CMOS), imaging sensor, etc.) are precisely aligned and oriented with respect to the sensing surface of the prism and the integrated cuvette. For example, the integrated cuvette and prism may include one or more kinematic features (e.g., grooves, conical recesses, chamfered slots, domed surfaces, pins, etc.) that mate with mating kinematic features located within the receiving space of the refractometer. Among other things, this kinematic connection (e.g., pin-in-slot connections, ball-in-cone connections, ball-and-pin connections, ball-and-chamfered slot connections, etc., and / or combinations thereof) can provide a reliable and accurate interconnection between the integrated cuvette and the receiving space of the refractometer. In some examples, the integrated cuvette and / or the receiving space of the refractometer may include anti-tamper features that can prevent the cuvette from being erroneously loaded into the receiving space of the refractometer.

[0007] The disclosed methods and systems enable plasma protein level measurements of a plasma donor's blood to be performed inline in an apheresis machine or other extracorporeal blood processing device. For example, a disposable tubing set includes an integrated cuvette and prism used by a refractometer associated with the apheresis machine to measure plasma protein levels. The method can begin when the disposable tubing set is interconnected with the apheresis machine. At this point, the integrated cuvette and prism are engaged with a receiving space in the refractometer. Once engaged, an optical path is established that carries source light into the prism and onto the sensing surface. The sensing surface then allows a portion of the light (called refracted light) to pass through to the whole blood in the cuvette. The sensing surface reflects the remaining portion of the light back into the prism and onto an external detection system. In some examples, the prism may have a first portion positioned adjacent to the light source (e.g., an LED) and a second portion positioned adjacent to a sensor (e.g., a CCD) spaced apart from the light source. The refractometer is then calibrated against the disposable tubing set, which includes the integrated cuvette and prism. During calibration, an anticoagulant (or other suitable solution, such as saline) is flowed along the fluid path through the tubing of the disposable tubing set and into the sensing space of the integrated cuvette adjacent to the sensing surface. With the anticoagulant disposed in the sensing space, light emitted by a light source (e.g., an LED) passes through the prism and onto the sensing surface of the integrated cuvette containing the anticoagulant in the sensing space. When the light interacts with the anticoagulant in the sensing space, a portion of the light is reflected back through the prism onto a sensor (e.g., a CCD). This reflected light generates a sensor reference signal that serves to establish a baseline, i.e., a reference pixel intensity pattern, for subsequent measurements of other blood components by the refractometer. In one example, the anticoagulant corresponds to sodium citrate (trisodium 2-hydroxypropane-1,2,3-tricarboxylic acid) and water.Next, when a plasma donor is connected to the disposable tubing set, for example, via a needle, catheter, or cannula, the whole blood flows along the fluid path through the sensing space of the integrated cuvette. Light emitted by the refractometer's light source passes through a prism and falls on the sensing surface of the integrated cuvette, which contains the whole blood. When the light source light is reflected off the sensing surface, the CCD detects an altered pixel intensity pattern (compared to that of the anticoagulant). The altered pattern is compared to the anticoagulant pixel pattern (as described below) to determine the protein concentration of the whole blood.

[0008] Although described herein as including a prism, the integrated cuvette may include, but is not limited to, a lens, a lens stack, and / or other optical element capable of transmitting light at least partially therethrough. In some examples, the prism may correspond to a lens and / or may include a prismatic optical element and at least one lens. As will be appreciated, the prism may be replaced by any optical shape that causes refraction / reflection of light.

[0009] In some examples, the light emitted by the light source (e.g., an LED) is set to a wavelength that cancels interference or noise caused by one or more components in whole blood. For example, the light source may be configured to emit light at approximately 420 nm ± 50 nm to allow refracted light encountering red blood cells in whole blood to be absorbed by the red blood cells (e.g., rather than reflected by the red blood cells). Notably, this selected wavelength of light may enable the refractometer to measure proteins in plasma even when red blood cells are in the background. A refractometer emitting light at 420 nm can detect reflected light from the prism sensing surface to determine protein levels in whole blood without the first refracted portion of light (which may be reflected by the RBCs and returned to the CCD sensor) by removing the contribution of red blood cells that may reflect light and cause signal noise.

[0010] In either case, if the measured protein level falls within an acceptable level (e.g., 6.0 g / dL-9.0 g / dL), the method may proceed by continuing apheresis. However, if the measured protein level falls outside the acceptable level (e.g., below 6.0 g / dL or above 9.0 g / dL), an alarm may be generated (e.g., audible, visual, etc., and / or a combination thereof), and the apheresis procedure may be stopped or aborted. In this case, the potential plasma donor may be disqualified from donating plasma, and the disposable tubing set, including the integrated cuvette and prism, may be disposed of or otherwise discarded prior to collecting plasma from the disqualified donor.

[0011] The methods and systems described herein can determine protein levels or other blood characteristics via refractive index measurements before and / or during an apheresis procedure. In one example, a refractometer can determine changes in protein concentration over time (e.g., during an apheresis procedure) for a plasma donor. This change can trigger an alarm to stop or pause apheresis, for example, when the protein concentration falls below an acceptable threshold. This acceptable threshold may correspond to a lower acceptable limit for protein in whole blood (e.g., 6.0 g / dL).

[0012] One aspect of the present disclosure is that an integrated cuvette and prism may be part of a disposable tubing set and may actually be disposable. Because refractive index measurements rely on a purely optical path, i.e., intimate contact between the optical sensing surface and the light emitted therethrough, if the cuvette is spaced apart from the prism or sensing surface, a gap will form between the cuvette and the light source and / or sensor. Even a small air gap (e.g., less than 1 micron) between the prism and the sensing surface can cause refractive interference that reduces the reliability of refractive index measurements of plasma proteins. At least one advantage of including a prism within the cuvette of a disposable tubing set is that it eliminates such gaps, making it possible to maintain measurement consistency between disposable tubing sets.

[0013] The in-line measurements performed by the refractometer and disposable, integrated cuvette described herein eliminate the need for time-consuming, complex, offline, multi-step measurements traditionally performed on blood samples. As can be appreciated, at least one advantage of the methods and systems disclosed herein is the ability to more quickly process plasma donors by, for example, allowing protein measurements to be performed when the plasma donor is connected to the apheresis machine (without going offline, disconnecting from the apheresis machine, or performing a separate process or step). As soon as the protein measurement is performed by the refractometer and determined to be within an acceptable range, the apheresis process begins on the same apheresis machine using the same disposable tubing set. In this case, whole blood extracted from the plasma donor may continue to flow through the integrated cuvette, configured to accept a flow of whole blood at a flow rate of at least up to 200 mL / min. The flow rate may be less than 200 mL / min and may include any flow rate value between 1.0 mL / min and 200 mL / min, inclusive.

[0014] Furthermore, the methods and systems described herein eliminate the need for all plasma donors to undergo a painful finger prick before donation. In any event, the disposable tubing set, including the integrated cuvette and prism, is discarded after use. This use may correspond to discarding the disposable tubing set after the plasma protein concentration is measured and determined to be outside the plasma donor's acceptable range (e.g., less than 6.0 g / dL or greater than 9.0 g / dL). Additionally or alternatively, this use may correspond to discarding the disposable tubing set after the plasma protein concentration is measured and determined to be within the plasma donor's acceptable range (e.g., greater than or equal to 6.0 g / dL and less than or equal to 9.0 g / dL) and the apheresis process is completed using the disposable tubing set. Notably, the ability to measure plasma protein levels for a plasma donor and either continue apheresis (if the plasma level is determined to be within the acceptable range) or terminate further processing (if the plasma level is determined to be outside the acceptable range) without changing settings provides a simple and efficient blood donation process.

[0015] It should be understood that the methods and systems disclosed herein are not limited to plasma donation or blood component separation, but may be used in therapeutic apheresis, blood processing procedures, and / or the like. Furthermore, the methods and systems disclosed herein may be used with any extracorporeal blood treatment, including, but not limited to, hemodialysis, hemodiafiltration (HDF), extracorporeal membrane oxygenation (ECMO), and / or the like. Thus, the methods and systems may be used with any extracorporeal blood treatment device, including, but not limited to, an apheresis device or system.

[0016] The foregoing is a simplified summary of the disclosure to provide an understanding of some aspects of the disclosure. This summary is not an extensive or comprehensive overview of the disclosure and its various aspects, embodiments, and configurations. It is not intended to identify key or critical elements of the disclosure, nor is it intended to delineate the scope of the disclosure; rather, it is intended to present selected concepts of the disclosure in a simplified form as a prelude to the more detailed description presented below. As will be appreciated, other aspects, embodiments, and configurations of the disclosure may be envisioned that utilize, alone or in combination, one or more of the features set forth above or described in detail below.

[0017] Numerous additional features and advantages are described herein, or will become apparent to those skilled in the art, upon consideration of the following detailed description and upon consideration of the drawings.

[0018] The accompanying drawings are incorporated into and constitute a part of this specification to illustrate several examples of the present disclosure. These drawings, together with the detailed description, explain the principles of the present disclosure. The drawings merely illustrate preferred and alternative examples of how the present disclosure may be made and used, and should not be construed as limiting the disclosure to only the examples shown and described. Further features and advantages will become apparent from the following more detailed description of various aspects, embodiments, and configurations of the present disclosure, as illustrated by the drawings referenced below. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a perspective view of the operating environment of an apheresis system and disposable tubing set including an integrated cuvette and prism, according to an embodiment of the present disclosure. [Figure 2A] FIG. 2A is a schematic diagram of a disposable tubing set including an integrated cuvette and prism according to an embodiment of the present disclosure. [Figure 2B] FIG. 2B is a functional schematic diagram of the disposable tubing set of FIG. 2A engaged with an apheresis device, according to an embodiment of the present disclosure. [Figure 3A] FIG. 3A is a detailed perspective view of an integrated cuvette and prism of a disposable tubing set and a separate refractometer according to an embodiment of the present disclosure. [Figure 3B] FIG. 3B is a schematic optical diagram of a refractometer operating with an integrated cuvette and prism of a disposable tubing set according to an embodiment of the present disclosure. [Figure 4] FIG. 4 is a perspective view of a prism formed on an integrated cuvette substrate according to an embodiment of the present disclosure. [Figure 5] FIG. 5 is a schematic optical diagram of light refracting through a plasma sample and reflecting from the prism sensing surface to the detector side of the prism, according to an embodiment of the present disclosure. [Figure 6A] FIG. 6A is a schematic optical diagram of light reflecting from a sensing surface of an integrated cuvette containing air to the detector side of the prism of the integrated cuvette, according to an embodiment of the present disclosure. [Figure 6B] FIG. 6B is a schematic optical diagram of light reflecting from a sensing surface of an integrated cuvette containing whole blood with a first plasma protein to a detector side of a prism of the integrated cuvette, according to an embodiment of the present disclosure. [Figure 6C] FIG. 6C is a schematic optical diagram of light reflecting from a sensing surface of an integrated cuvette containing whole blood with a second plasma protein to the detector side of the prism of the integrated cuvette, according to an embodiment of the present disclosure. [Figure 7] FIG. 7 is a graph of light intensity versus pixel position measured by a refractometer sensor detecting the reflectance of various fluids, according to an embodiment of the present disclosure. [Figure 8] FIG. 8 is a graph of light absorption by red blood cells at various wavelengths, according to an embodiment of the present disclosure. [Figure 9] FIG. 9 is a flow diagram of a method for automatically performing in-line testing of protein levels in whole blood obtained from a plasma donor connected to an apheresis device according to an embodiment of the present disclosure. [Figure 10]FIG. 10 is a flow diagram of a method for calibrating a refractometer associated with an apheresis device according to an embodiment of the present disclosure. [Figure 11] FIG. 11 is a flow diagram of a method for determining protein levels of a plasma donor while the plasma donor is connected to an apheresis device according to an embodiment of the present disclosure. [Figure 12A] FIG. 12A is a graph of sensor readings using various concentrations of calibration liquid to produce an anticoagulant calibration pixel pattern, according to an embodiment of the present disclosure. [Figure 12B] FIG. 12B is a flow diagram of a method for calculating pixel shift according to an embodiment of the present disclosure. [Figure 12C] FIG. 12C is a flow diagram of a method for calculating the proportionality constant K according to an embodiment of the present disclosure. [Figure 12D] FIG. 12D is a graph of an exemplary first pixel pattern used to determine the proportionality constant K. [Figure 12E] FIG. 12E is a graph of an exemplary second pixel pattern used to determine the proportionality constant K. [Figure 12F] FIG. 12F is a graph of an exemplary third pixel pattern used to determine the proportionality constant K. [Figure 12G] FIG. 12G is a graph of an exemplary fourth pixel pattern used to determine the proportionality constant K. [Figure 13A] FIG. 13A is an exploded perspective view of an integrated cuvette and prism of a disposable tubing set according to an embodiment of the present disclosure. [Figure 13B] FIG. 13B is a perspective view of an integrated cuvette and prism of a disposable tubing set according to an embodiment of the present disclosure. [Figure 14A] FIG. 14A is a perspective view of a further exemplary refractometer according to the present disclosure. [Figure 14B] FIG. 14B is a cross-sectional view of the refractometer of FIG. 14A taken along line 14B-14B. DETAILED DESCRIPTION OF THE INVENTION

[0020] Before describing any embodiments of the present disclosure in detail, it is to be understood that the disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings. The present disclosure is capable of other embodiments and of being practiced or carried out in various ways. It is also to be understood that the phraseology and terminology used herein are for the purpose of description and are not to be regarded as limiting. The use of "including," "comprising," or "having," and variations thereof, herein is meant to encompass the items listed thereafter and equivalents thereof, as well as additional items. Furthermore, the present disclosure may use examples to illustrate one or more aspects. Unless otherwise specified, the use or recitation of one or more examples (which may be indicated by "for example," "by way of example," "eg," "etc.", or similar language) is not intended to and does not limit the scope of the disclosure.

[0021] The following description provides embodiments only and is not intended to limit the scope, applicability, or configuration of the claims. Rather, the following description will provide those skilled in the art with an effective description for implementing the described embodiments. It should be understood that various changes can be made in the function and arrangement of elements without departing from the spirit and scope of the appended claims.

[0022] Various aspects of the present disclosure are described herein with reference to drawings that are schematic illustrations of idealized configurations.

[0023] Referring now to FIG. 1 , a perspective view of the operating environment of an apheresis system 100 (e.g., an extracorporeal blood processing device) and a disposable tubing set 120 including an integrated cuvette and prism is shown, according to an embodiment of the present disclosure. The operating environment may include the apheresis system 100, a donor 102, and one or more connecting members (e.g., donor supply tubing 104, inlet tubing 108, anticoagulant tubing 110, etc.) extending from the donor 102 to the apheresis system 100 and / or vice versa. The terms “donor,” “plasma donor,” and variations thereof are used interchangeably herein. As shown in FIG. 1 , the donor supply tubing 104 may be fluidly connected to at least one blood vessel, e.g., a vein, of the donor 102 via venipuncture. For example, a catheter, cannula, or needle connected to the end of the donor supply tubing 104 may be inserted through the donor 102's skin into a target site, i.e., a vein. This connection may provide a venous pathway for blood (e.g., whole blood) to flow from donor 102 to apheresis system 100 and / or for blood components to flow back to donor 102. In some embodiments, the fluid paths and connecting members may form an extracorporeal tubing circuit of the disposable tubing set of apheresis system 100.

[0024] Blood from the donor 102 can flow along donor supply tubing 104, through tubing connector 106, and along inlet tubing 108 into an integrated cuvette of the disposable tubing set 120. The integrated cuvette can mate with a receiving space 130 of a refractometer associated with the apheresis system 100. In some examples, the receiving space 130 can have a lid or door covering the area housing the refractometer. The disposable tubing set can include one or more fluid control paths and valves for selectively controlling the flow of blood to and / or from the donor 102. The apheresis system 100 can provide a supply of anticoagulant contained in an anticoagulant bag 114. The anticoagulant can be pumped through at least the anticoagulant tubing 110 and the tubing connector 106 to prevent clotting of blood within the disposable tubing set 120 and the apheresis system 100. Although described as being contained in a bag, it should be understood that the anticoagulant may be contained in a bottle, reservoir, well, or other container.

[0025] The anticoagulant may include, but is not limited to, one or more of citrate and / or unfractionated heparin, as long as the chemical composition does not change from one apheresis procedure to the next. When the chemical composition does not change, the calibration anticoagulant solution always simulates the same level of plasma protein concentration. For example, the anticoagulant cited in this disclosure always simulates a plasma protein content of 2.4 gm / dL, as long as the chemical composition does not change. The anticoagulant bag and other bags or bottles described herein may be made from, for example, but not limited to, one or more of polyvinyl chloride (PVC), plasticized PVC, polyethylene, ethylene with vinyl acetate (EVA), rubber, silicone, thermoplastics, thermoplastic elastomers, polymers, copolymers, and / or combinations thereof. The volume of anticoagulant in the anticoagulant bag 114 may vary based on various factors, including the mass of the donor 102, the volumetric flow rate of blood from the donor 102, etc. In one example, the volume within anticoagulant bag 114 may be 250-500 mL, although the volume within anticoagulant bag 114 may be larger or smaller than this volume.

[0026] In some embodiments, the apheresis system 100 can include a plasma collection bottle 122 or container, saline contained in a saline bag 118, and one or more lines or tubing 116, 120 (e.g., fluid transfer tubing, etc.) connecting the saline bag 118 and the plasma collection bottle 122 to a disposable tubing set 120 of the apheresis system 100. The amount of saline provided in the saline bag 118 can be 500-800 mL, although the volume within the saline bag 118 can be more or less than this amount. An example volume of a blood component, such as plasma, can be 880 mL. Thus, the plasma collection bottle 122 can contain at least this amount of plasma. In some embodiments, the plasma collection bottle 122 can include a connection point located approximately at, adjacent to, or physically close to the lowest portion of the plasma collection bottle 122 (e.g., when the plasma collection bottle 122 is placed in a plasma collection cradle). The connection point may include one or more connectors configured to interconnect with a plasma tube for receiving and / or transporting plasma. Locating the connection point at the bottom of the plasma collection bottle 122 allows plasma contained in the plasma collection bottle 122 to be returned from the plasma tube through a line as described herein without trapping air bubbles, etc. In some embodiments, the plasma collection bottle 122 may be configured as a flexible bag, a rigid container, and / or other container, and thus is not limited to a bottle or bottle-like container.

[0027] Examples of apheresis systems, plasmapheresis systems, and other separation systems that may be used with embodiments of the present disclosure, such as apheresis system 100, include, but are not limited to, the RIKA plasma collection system, the SPECTRA OPTIA® apheresis system, the COBE® Spectra apheresis system, and the TRIMA ACCEL® automated blood collection system (these systems are manufactured by Terumo BCT, located in Lakewood, Colorado).

[0028] 2A shows a schematic diagram of a disposable tubing set 120 including an integrated cuvette and prism 124 according to an embodiment of the present disclosure. The disposable tubing set 120 includes tubing (e.g., one or more of donor supply tubing 104, inlet tubing 108, anticoagulant tubing 110, loop outlet tubing 112, saline tubing 116, plasma tubing 120, etc.), connectors (e.g., one or more of tubing connector 106, saline / plasma tubing y-connector 280, tubing fitting 204, tubing fitting 208, bag spike fitting 212, etc.), a soft cassette 240, and a blood component collection loop 220.

[0029] The tubing is any tubing having a central lumen configured to carry a fluid. The tubing can be formed from polyvinyl chloride (PVC), plasticized PVC, polyethylene, ethylene with vinyl acetate (EVA), rubber, polymers, copolymers, and / or combinations thereof. The connector is configured to fluidly interconnect with the tubing (e.g., at one or more ends of the tubing, etc.). The connector may be inserted into the central lumen of the tubing and / or attached to the exterior surface of the tubing. In some embodiments, the connector may be configured with various fittings (e.g., Luer fittings, twist connections, and / or other stoma couplings, etc.), thereby providing a universal and / or reliable interconnection to one or more other fittings, connectors, tubing, needles, catheters, cannulas, and / or medical accessories. In one embodiment, the bag spike fitting 212 may be configured for insertion into a receiving bag (e.g., saline bag 118, etc.).

[0030] The blood component collection loop 220 includes a flexible loop 224 disposed between a system securement loop connector 228 and a filler loop connector 232. The flexible loop 224 may be configured as a hollow flexible tube configured to receive and / or accommodate at least a portion of the inlet tubing 108 and the loop outlet tubing 112. In some embodiments, the flexible loop 224 may be formed from a highly flexible thermoplastic elastomer capable of transmitting torsion from one end of the flexible loop 224 to the other. These types of elastomers can provide the flexibility of rubber while maintaining the strength and torque characteristics of plastic. Examples of thermoplastic elastomers include, but are not limited to, copolyesters, DuPont™ Hytrel® thermoplastic elastomers, Eastman Neostar™ elastomers, Celanese Riteflex® elastomers, TOYOBO PELPRENE®, and / or elastomers from other manufacturers that provide high flexibility and strength characteristics.

[0031] In some embodiments, blood component collection loop 220 includes a blood component collection bladder 236 having a bladder loop end 240A and a bladder free end 240B. Blood component collection bladder 236 includes a first collection flow chamber 244 connected to flexible loop 224 with a filler loop connector 232. In particular, fluid can flow between inlet tube 108 and first collection flow chamber 244, and / or vice versa, via flexible loop 224 and connectors 228, 232. Fluid flowing from bladder loop end 240A along first collection flow chamber 244 toward bladder free end 240B can reach flow chamber transition 248 and enter second collection flow chamber 252. In one embodiment, second collection flow chamber 252 is interconnected to flexible loop 224 with filler loop connector 232. In particular, fluid can flow between the loop outlet tube 112 and the second collection flow chamber 252 and / or vice versa via the flexible loop 224 and connectors 228, 232.

[0032] 2B is a functional schematic diagram of a disposable tubing set 120 engaged with an apheresis system 100, according to an embodiment of the present disclosure. This description illustrates the components previously described in functional diagrams in FIGS. 1-2A to illustrate the interaction of apheresis system 100 and disposable tubing set 120 to extract plasma or other blood components from the whole blood of a donor 102 during an apheresis procedure or process.

[0033] The apheresis system 100 may include an anticoagulant (AC) pump 216. The AC pump 216 pumps fluid from the AC bag 114 into the AC tubing 110. The AC pump 216, the AC tubing 110, and / or the AC bag 114 may be as described above. The AC tubing 110 may also include an AC air detection sensor (ADS) to detect air or fluid within the AC tubing 110. The AC ADS may be any optical, ultrasonic, or other type of sensor capable of detecting the presence of fluid or air within the AC tubing 110 and providing a signal to the controller 268 of the apheresis system 100. An example of an AC ADS type may be a SONOCHECK ABD05 sensor manufactured by SONOTEC US Inc., or other similar sensors. The AC tubing 110 intersects with and is fluidly associated with the donor supply tubing 104 and the inlet tubing 108 at a tubing connector 106. The tube connector 106 may be any type of connection between the tubes 110, 104 and / or 108, as previously described.

[0034] Donor supply tubing 104 extends from donor 102, which may be punctured with a lumen needle, cannula, catheter, or other device, allowing whole blood to flow from donor 102 into apheresis system 100 and blood components to flow back to donor 102. Tubing 108 extends to an integrated cuvette and prism 124. The integrated cuvette and prism 124 may correspond to a disposable plastic portion of disposable tubing set 120 attached to tubing 108 of disposable tubing set 120. When disposable tubing set 120 is loaded into apheresis system 100, the integrated cuvette and prism 124 engages with a receiving space 130 of apheresis system 100. The receiving space 130 may include kinematic mounting features that allow the integrated cuvette and prism 124 to be precisely positioned and positioned within the receiving space 130. The integrated cuvette and prism 124 includes an optically transparent surface and a prism formed from the optically transparent surface. In some examples, the prism and optically transparent surface are formed from a single piece of plastic. The optically transparent surface of the integrated cuvette and prism 124 allows light to be emitted toward the fluid contained inside the integrated cuvette and prism 124, and further allows reflected light to be detected by the refractometer 260. The refractometer 260 may include a light source 262 (e.g., an LED, etc.) configured to emit light toward the fluid in the integrated cuvette and prism 124 (e.g., through the prism to a first side or illumination side of the prism). When the emitted light interacts with the fluid in the integrated cuvette and prism 124, reflected light travels through the prism to a second side or detector side of the prism and to a sensor 266 (e.g., a CCD, etc.) of the refractometer 260. The reflected light travels toward the sensor at different angles depending on the fluid in the integrated cuvette and prism 124. Refractometer 260 includes a communication / power cable 264 that runs to and from a controller 268 (e.g., a processor, etc.) of apheresis system 100.The controller 268 may control the operation of the refractometer 260 as described herein.

[0035] In some embodiments, the controller 268, i.e., the processor, corresponds to one or more computer processing devices. For example, the processor may be provided as silicon, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), any other type of integrated circuit (IC) chip, a collection of IC chips, and / or the like. In some embodiments, the processor may be provided as a central processing unit (CPU), a microprocessor, or multiple microprocessors configured to execute a set of instructions stored in memory. When executing the set of instructions stored in memory, the processor may enable various communication, activation of a light source, reception of light reflectance detection information from a sensor, calibration of the refractometer 260, determination of plasma protein levels, and / or other interactive functions of the apheresis system 100, providing the ability to establish and maintain communication sessions between communicating devices over a communication network when certain predetermined conditions are met. The processor may be embodied as a virtual processor executing on one or more physical processors. Execution of a virtual processor may be distributed across multiple physical processors, or one physical processor may execute one or more virtual processors. A virtual processor appears to a process as a physical processor executes the process, while a particular underlying physical processor may be dynamically allocated before or during execution of the virtual processor, and instruction stacks and pointers, register contents, and / or other values maintained by the virtual processor for the execution of the process may be transferred to other physical processors. Advantageously, physical processors can be added, removed, or reassigned without affecting the virtual processor execution of the process. For example, a processor may be one of multiple virtual processors executing on multiple physical processors (e.g., a "cloud," "farm," array, etc.) and may be presented to the process herein as a dedicated processor. Additionally or alternatively, a physical processor may execute a virtual processor to provide an alternative instruction set compared to the instruction set of the virtual processor (e.g., an "emulator").As an advantage, a process compiled to run on a processor having a first instruction set (e.g., Virtual Address Extension (VAX)) can be executed by a processor executing a second instruction set (e.g., Intel® 9xx chipset code) by executing a virtual processor having the first instruction set (e.g., a VAX emulator).

[0036] As described above, the controller, i.e., processor, may execute a set of instructions stored in memory. The memory, i.e., storage memory, may correspond to any type of non-transitory computer-readable medium. In some embodiments, the memory may comprise volatile or non-volatile memory and a controller therefor. Non-limiting examples of storage memory that may be utilized in the apheresis system 100 and / or refractometer 260 include random access memory (“RAM”), read-only memory (“ROM”), buffer memory, flash memory, solid-state memory, or variations thereof. Any of these memory types may be considered a non-transitory computer memory device, even if the data stored therein may be changed one or more times. The memory may be used to store information about communications, identification, conditional requirements, time, compliance, calibration settings, protein levels, historical data, etc. In some embodiments, the memory may be configured to store rules and / or instruction sets in addition to temporarily storing data for the processor to perform various types of routines or functions. While not shown, the memory may include instructions that enable the processor to store data in and retrieve information from memory storage devices. In some embodiments, the memory storage device or the data stored therein may be stored internal to the apheresis system 100 and / or refractometer 260 or on a separate server.

[0037] A donor air detection sensor may be disposed on or within the tube 108 to detect the presence of fluid and / or air within the tube 108 .

[0038] The soft cassette can include a first cassette port that functions as and / or includes and / or is adjacent to a "Y" connector or "Y" section or branch, separating the tubing 108 into a first bypass branch and a first tubing section. The two tubing sections are reconnected at a second cassette port that also functions as and / or includes and / or is adjacent to a second "Y" connector or "Y" section. The tubing is divided into two by a fluid sensor that separates the tubing into the first and second bypass branches. Similarly, the tubing is divided into two by a drip chamber that separates the tubing into the first and second tubing sections.

[0039] The first tubing section includes a first fluid control valve. The second tubing section similarly includes a second fluid control valve. The first bypass branch similarly includes an inlet fluid control valve. Thus, depending on the configuration and operation of apheresis system 100, various sections of tubing can be isolated by valves.

[0040] The drip chamber is disposed between the first and second tubing sections and is capable of collecting a predetermined amount of whole blood and / or high hematocrit blood (blood with a high percentage of red blood cells) depending on the operation of the apheresis system 100. The fluid sensor is disposed between the first and second bypass branches.

[0041] The loop inlet tubing can be connected to a second cassette port as described in connection with FIG. 2A and can connect the soft cassette to the flexible loop 224. The loop inlet tubing can include a sensor located on, within, or with the tubing prior to connection with the system secure loop connector 228 of the flexible loop 224. The pressure sensor (CPS) can detect one or more of, but is not limited to, pressure, presence or absence of fluid or air within the tubing, and / or possibly other properties of the fluid. Additionally, a draw pump can pump fluid through the tubing and away from or into the soft cassette.

[0042] Two or more different tubes can be connected to the flexible loop 224 via the system fixation loop connector 228, and two or more different tubes can supply fluid to or receive fluid from the blood component collection bladder 236. The loop outlet tube 112 exits the flexible loop 224 through the system fixation loop connector 228. This loop outlet tube 112 can also include another line sensor disposed on or within the loop outlet tube to detect fluid, air, intracellular concentrations, color, and / or color changes in the fluid exiting the flexible loop 224. The line sensor may be the same or similar in type and / or function to the sensors previously described. A second CPS sensor or fluid sensor may be disposed within or on the line 112. The sensor may detect one or more of, but is not limited to, the presence or absence of fluid in the tube 112, the pressure, and / or other characteristics of the fluid in the tube 112. Similarly, the sensor may be the same or similar in type and / or function to the sensors previously described.

[0043] The loop outlet tubing 112 then passes through a plasma air detection sensor before splitting into saline tubing 116 and plasma tubing 120 at a saline-plasma tubing y-connector 280. A return pump 212 may interface with the loop outlet tubing 112, allowing fluid or air to flow through the tubing 112 from the flexible loop 224 or from the saline bag 118 and / or plasma collection bottle 122.

[0044] The saline bag 118 and associated tubing may be as previously described and may supply saline to the original donor 102 through the system 200. A saline flow control valve 288 may isolate the saline bag 118 from the rest of the system 200. Additionally, a plasma collection bottle 122 may receive plasma from the flexible loop 224 once it has been processed or separated from the whole blood. The plasma collection bottle 122 may be selectively isolated from the system by the plasma flow control valve.

[0045] 3A is a detailed perspective view of the integrated cuvette and prism 124 and separate refractometer 260 of the disposable tubing set 120 according to an embodiment of the present disclosure. As shown in FIG. 3A, the integrated cuvette and prism 124 is attached to the tubing 108 and forms part of the disposable tubing set 120. For example, after an apheresis procedure is completed, the entire disposable tubing set 120, including the integrated cuvette and prism 124, is discarded. Stated another way, the disposable tubing set, including the integrated cuvette and prism 124, may be designed for single use only.

[0046] The integrated cuvette and prism 124 includes an integrated prism formed from a surface of the integrated cuvette and prism 124. In one example, the prism and a portion of the integrated cuvette and prism 124 may be injection molded as a single piece. As whole blood flows along the fluid flow path of the tube 108, the whole blood may enter a portion of the integrated cuvette and prism 124 positioned adjacent to the refractometer 260. The refractometer 260 is shown in FIG. 3A without a housing and engagement features for clarity of disclosure. More specifically, a light source (e.g., an LED) 262 of the refractometer 260 is shown emitting light toward the whole blood (through the integrated prism of the integrated cuvette and prism 124) and a sensor (e.g., a CCD) receiving reflected light from the whole blood (through the integrated prism of the integrated cuvette and prism 124). Refractometer 260 is configured to measure protein levels in whole blood as it flows along the fluid flow path through integrated cuvette and prism 124. These measurements can be made at flow rates up to 200 mL / min.

[0047] In some examples, an ultrasonic separator (e.g., an ultrasonic transducer, a piezoelectric transducer, etc.) 312 (FIG. 3A) is positioned adjacent to at least one side of the integrated cuvette and prism 124. The ultrasonic separator is activated (e.g., by a controller, etc.) to promote sedimentation of red blood cells 310 away from the sensing surface of the integrated cuvette and prism 124. This promoted sedimentation occurs when the integrated components are oriented such that gravity pulls the cells away from the sensing surface 314 (FIG. 3B). In one example, the integrated cuvette and prism 124 is oriented such that the integrated prism is located on the side of the integrated cuvette and prism 124 that faces away from the direction of gravity (e.g., the gravity vector, etc.). For example, the integrated prism 126 can be positioned on the top side of the integrated cuvette and prism 124. This allows gravity to assist in pulling the red blood cells 310 away from the sensing surface and causing them to settle, allowing for a clearer refractive response from the plasma in the whole blood. As shown, gravity causes the red blood cells 310 shown in FIG. 3B to move away from the sensing surface of the integrated cuvette and prism 124. Also, pausing the flow of whole blood being analyzed preferably allows gravity to pull the red blood cells away from the sensing surface, thereby reducing the amount of light reflected by the red blood cells and improving the sensor reading of the refractometer 260.

[0048] 3B shows a schematic optical diagram of a refractometer 260 operating with the integrated cuvette and prism 124 of a disposable tubing set 120 according to an embodiment of the present disclosure. As whole blood passes over the sensing surface of the integrated cuvette and prism 124, the refractometer 260 emits light from a light source toward the whole blood on the sensing surface of the integrated prism. A portion of the emitted light enters the whole blood as refracted light 272, and a portion of the emitted light is reflected from the sensing surface toward a sensor 266 as reflected light 274. An altered pixel intensity pattern (compared to that of an anticoagulant) is detected by the optical sensor 266 (e.g., a CCD) in response to the plasma protein level of the whole blood. The altered pixel intensity pattern of the whole blood is then compared to a reference pattern of an anticoagulant solution, and the plasma protein concentration is determined based on the difference in pixel intensity patterns (described further below).

[0049] In some examples, the light source 262 emits light at a specific wavelength or multiple specific wavelengths to obtain more accurate results for whole blood protein level measurements. For example, the light source may emit light at 420 nm, in which case the red blood cells will absorb the refracted light rather than reflecting it back toward the sensor. In this manner, reflected light interference 268 from the red blood cells with plasma protein level measurements can be reduced or even eliminated. That is, if the light source is configured to emit light at 420 nm, the reflected light 268 from the red blood cells shown in FIG. 3B is eliminated because the 420 nm light is absorbed by the red blood cells.

[0050] FIG. 4 shows a perspective view of an integrated prism 126 formed within an integrated cuvette substrate according to an embodiment of the present disclosure. The integrated prism 126 of the integrated cuvette and prism 124 can be made of any suitable material. For example, the prism 126 can be injection molded from a plastic material (e.g., polyethylene terephthalate glycol or polycarbonate) or made of glass. The plastic material can provide a transparent optical path from the outside of the integrated prism 126 to the interior space of the integrated cuvette and prism 124 through which whole blood passes. The integrated prism 126 can have any suitable shape. For example, the integrated prism 126 can be formed in the shape of a triangular prism, an M-shaped prism, a prism having at least one triangular prism portion and at least one curved surface (e.g., a concave and / or convex surface), and / or a combination thereof. In any case, the integrated prism has a sensor side and a light source side. 2B , for example, when the integrated cuvette and prism 124 of the disposable tubing set 120 is engaged with the receiving space 130 of the apheresis system 100, the light source side (LS) is positioned adjacent to the light source of the refractometer 260, and the sensor or detector side (DS) is positioned adjacent to the sensor of the refractometer 260. In some examples, the light source is spaced apart from the sensor of the refractometer 260 and offset by a distance.

[0051] As shown in the optical schematic diagram of Figure 5, M-prism 126 includes a removed area between the light source side LS and the detector side DS of the integrated prism. This removed area can reduce the amount of material required for the integrated prism, improve molding characteristics, and / or provide clearance for mating with a portion of refractometer 260. Figure 5 shows that light is emitted from the light source side LS, then a portion is incident on and refracted through the plasma sample, and the remaining portion is reflected from the sensitive surface of the prism to the detector side DS.

[0052] 6A-6C show schematic optical diagrams of light emitted from a light source side LS of the integrated prism through a first portion of the integrated prism (e.g., having a triangular prism shape) and reflected from the sensing surface of the integrated cuvette and prism 124 through a second portion of the integrated prism (e.g., having a semi-curved shape) to a detector side DS of the integrated cuvette and prism 124 in accordance with an embodiment of the present disclosure.

[0053] In the schematic optical diagram of Figure 6A, the tube 108 contains air, and all of the light from the light source is reflected toward the detector; no light is refracted. In Figure 6B, the tube 108 contains whole blood having a plasma protein level of 6.0 g / dL, which is delivered to the integrated cuvette and prism 124. In this example, the light reflected toward the detector is reflected onto the sensor (shown in dashed lines) to generate a pixel intensity pattern that illuminates pixels in a first pixel location region P1. In Figure 6C, the tube 108 contains whole blood having a plasma protein level of 9.0 g / dL, which is delivered to the integrated cuvette and prism 124. In Figure 6C, the light reflected toward the detector is reflected onto the sensor (shown in dashed lines) to generate a pixel intensity pattern that illuminates pixels in a second pixel location region P2. When whole blood is measured by refractometer 260 and produces a reflected light that falls between (and including) these two boundary conditions (e.g., P1 and P2), donor 102 is eligible for plasma donation, and apheresis is automatically initiated (e.g., without further setup, connections, etc.). However, when whole blood is measured by refractometer 260 and produces a reflected light that falls outside of these two boundary conditions (e.g., P1 and P2), donor 102 is determined to be ineligible for plasma donation, and the apheresis process is automatically aborted. In some examples, an alarm is generated along with a message conveying donor 102's ineligibility and / or information regarding the measured plasma protein levels.

[0054] FIG. 7 shows a graph of light intensity versus pixel position measured by a sensor of a refractometer 260 detecting reflected light from various fluids, according to an embodiment of the present disclosure. In some examples, the "no sample" line corresponds to a baseline or reference value associated with total reflection of the source light when air is in contact with the prism sensing surface (as shown in FIG. 6A). By establishing a calibration reference value using an anticoagulant, the refractometer 260 can determine the pixel position shift between the anticoagulant and a whole blood test sample. The anticoagulant pixel position relative to a selected light intensity value is determined. Once the whole blood sample is placed in the cuvette, the pixel position relative to the selected light intensity value is determined. The difference between these two pixel positions (referred to herein as "pixel shift") is proportional to the plasma protein content. For example, FIG. 7 shows pixel intensities from two whole blood samples, one containing a plasma protein level of 5.9 g / dL and the second containing a plasma protein level of 9.0 g / dL. For a 5.9 g / dL sample, the reflected light will illuminate pixel location 1800 of the sensor with a light intensity of approximately 158. For a whole blood sample with a plasma protein level of 9.0 g / dL, the pixel location illuminated with a light intensity of approximately 158 will shift to location 1020. The shift in pixel location of equal intensity (pixel shift = 1800 - 1020) is proportional to the difference in plasma protein levels. Among other things, this proportionality and method allows the refractometer 260 to be calibrated using a known solution, such as an anticoagulant that simulates a plasma protein content of 2.4 g / dL, each time a new integrated cuvette and prism 124 of the disposable tubing set 120 is engaged with the apheresis system 100. Therefore, manufacturing variations or variations in the seating position of the integrated cuvette and prism 124 within the receiving space 130 are effectively counteracted by comparing the pixel shift between the sensor pixel illuminated by light reflected from the anticoagulant and the sensor pixel illuminated by light reflected from the whole blood being tested, and therefore such variations do not adversely affect the accuracy of the test results.

[0055] FIG. 8 shows a graph of light absorption by red blood cells at various wavelengths according to an embodiment of the present disclosure. As shown in the graph of FIG. 8, light absorption by red blood cells is greatest at 420 nm. By setting the light source, i.e., LED, of the refractometer 260 to emit light at 420 nm, interference in whole blood measurements can be reduced. For example, refracted light from a 420 nm light source is absorbed by red blood cells rather than reflected or scattered. Meanwhile, 420 nm light from the light source is reflected from the prism sensing surface due to the presence of plasma in whole blood. In some cases, use of a 420 nm light source can reduce or eliminate light reflection and scattering from red blood cells from measurements by the refractometer sensor. Other suitable wavelengths of light emitted by the refractometer that can be absorbed by red blood cells include, but are not limited to, about 275 nm, about 375 nm, and wavelengths within the range of about 550 nm to about 600 nm.

[0056] FIG. 9 is a flow diagram of a method 900 for automatically performing in-line testing of protein levels in whole blood obtained from a donor 102 connected to an apheresis system 100, according to an embodiment of the present disclosure. The general sequence of steps in method 900 is shown in FIG. 9. Generally, method 900 begins with step 904 and ends with step 932. Method 900 may include more or fewer steps, or the steps may be ordered differently than shown in FIG. 9. Method 900 may be executed by a computer system, controller, processor, centrifuge microcontroller, and / or other device, and may be implemented at least in part as a set of computer-executable instructions encoded or stored on a computer-readable medium. In other configurations, method 900 may be implemented at least in part by a series of components, circuits, gates, etc., configured in a hardware device, such as a system-on-chip (SOC), application-specific integrated circuit (ASIC), and / or field-programmable gate array (FPGA). Method 900 will be described below with reference to the systems, devices, valves, pumps, sensors, components, circuits, modules, software, data structures, signaling processes, models, environments, apheresis systems, etc., described in connection with Figures 1-8.

[0057] Method 900 begins by attaching disposable tubing set 120 to apheresis device or system 100 (step 904). In this step, the tubing of disposable tubing set 120 is inserted into a receiving area of apheresis system 100 and associated with a pump, valve, bag, collection container, etc.

[0058] Next, the integrated cuvette and prism 124 is engaged with the refractometer receiving space 130 of the apheresis system 100 (step 908). In some examples, engaging the integrated cuvette and prism 124 includes clamping a body of the integrated cuvette and prism 124 to a recessed area of the apheresis system 100. The receiving space 130 may include one or more kinematic features for precisely aligning the integrated cuvette and prism 124 of the disposable tubing set 120 with the refractometer 260 of the apheresis system 100. In one example, the integrated cuvette and prism 124 may be placed in a bracket or holder of the apheresis system 100 within the receiving space 130, and a lid or door may enclose the integrated cuvette and prism 124 within the receiving space 130. The door can apply pressure to the integrated cuvette and prism 124, forcing at least one face of the integrated cuvette and prism 124 against a support surface within the receiving space 130. In some examples, the door is held closed with a knob, clamp, magnet, and / or latch.

[0059] The method 900 proceeds by connecting the donor 102 to the disposable tubing set 120 (step 912). In some examples, this connection involves inserting a needle, catheter, or cannula into the donor 102's vein (e.g., in the donor's 102's arm) and ensuring blood flows from the donor 102 along the donor supply tubing 104. The donor 102 remains connected to the disposable tubing set 120 while the apheresis system 100 is operating.

[0060] Before initiating the apheresis process, method 900 proceeds by calibrating refractometer 260 associated with apheresis system 100 (step 916). Calibration allows different disposable tubing sets 120 with integrated cuvettes and prisms 124 to be engaged with apheresis system 100 and allows a baseline, or calibration reference value, to be established for the integrated cuvettes and prisms 124 specific to the disposable tubing set 120. Further details regarding calibration are described in conjunction with FIG. 10.

[0061] Once calibrated, the method 900 proceeds by pumping whole blood from the donor 102 into the integrated cuvette and prism 124 (step 920). For example, following the fluid path shown in FIG. 2B , a draw pump draws whole blood from the donor 102 along the donor supply tubing 104, through the tubing connector 106, along the inlet tubing 108, and into and through the integrated cuvette and prism 124 (step 920). In some examples, the integrated cuvette and prism 124 may be attached to the inlet tubing downstream of the tubing connector and upstream of the soft cassette. When connected to the apheresis system 100, the integrated cuvette and prism 124 is positioned upstream of the other pumps. The integrated cuvette and prism 124 is positioned adjacent to a refractometer 260, which includes a light source and a sensor.

[0062] The method 900 then proceeds by operating the refractometer 260 (step 924) with whole blood present in the integrated cuvette and prism 124. In some examples, the refractometer 260 is operated with whole blood passing through the integrated cuvette and prism 124 from one end to the other. In some examples, the flow may be stopped when the whole blood fills the chamber of the integrated cuvette and prism 124. Operating the refractometer includes causing a light source to emit 420 nm light in a direction toward the integrated cuvette and prism 124, more specifically, through the integrated prism and onto the whole blood contained therein. As the light is emitted, a sensor detects reflected light on one or more pixels, pixel areas, and / or pixel locations.

[0063] Based on the reflected light and the calibration standard, method 900 then determines the plasma protein level in the whole blood (step 928). For example, the reflected light caused by whole blood projects an altered pixel intensity pattern onto the sensor compared to the anticoagulant calibration standard pattern. The shift in the pixel pattern between the calibration solution and the whole blood can be used to determine the plasma protein content of the whole blood. Further details regarding this determination are described with reference to FIGS. 11 and 12A-12G.

[0064] If the plasma protein level is determined to be within a predetermined "acceptable" range, e.g., 6.0 g / dL to 9.0 g / dL, the donor 102 is deemed eligible to donate plasma, and the apheresis process is automatically initiated by the apheresis system (step 932). This apheresis process is initiated automatically without any further device setup or processing of the donor 102, the apheresis system 100, and / or any connection changes to the donor 102. However, if the plasma protein level is determined to be outside the predetermined acceptable range (e.g., below 6.0 g / dL or above 9.0 g / dL), the donor 102 is deemed ineligible to donate plasma, and the initiation of the apheresis process is aborted. In the latter case, the disposable tubing set 120 is removed from the apheresis system 100 and discarded (e.g., disposed of). The methods and systems described herein allow for measurement and apheresis to occur in a single setting (e.g., in-line), resulting in less waste (e.g., no labor required to obtain plasma protein content, no finger pricks, capillary tubes, etc.) and fewer steps to be performed (e.g., no need to separately obtain a sample, centrifuge the sample, test the sample using a handheld refractometer, etc., before connecting the donor 102 to the apheresis system 100). As can be appreciated, the present disclosure allows for efficient and cost-effective processing of donors 102 through apheresis.

[0065] FIG. 10 is a flow diagram of a method 1000 for automatically calibrating a refractometer 260 associated with an apheresis system 100, according to an embodiment of the present disclosure. Method 1000 may correspond to step 916 described in connection with FIG. 9. The general sequence of steps of method 1000 is shown in FIG. 10. Generally, method 1000 begins with step 1004 and ends with step 1020. Method 1000 may include more or fewer steps, or the steps may be ordered differently than shown in FIG. 10. Method 1000 may be executed by a computer system, controller, processor, centrifuge microcontroller, and / or other device and may be implemented, at least in part, as a set of computer-executable instructions encoded on or stored on a computer-readable medium. In other configurations, method 1000 may be performed, at least in part, by a series of components, circuits, gates, etc. implemented in a hardware device, such as, for example, a system-on-chip (SOC), an application-specific integrated circuit (ASIC), and / or a field-programmable gate array (FPGA). Method 1000 will be described below with reference to the systems, devices, valves, pumps, sensors, components, circuits, modules, software, data structures, signal transmission processes, models, environments, apheresis systems, methods, etc., described in connection with FIGS.

[0066] Method 1000 begins by flowing anticoagulant from AC bag 114 through AC tubing 110 and into integrated cuvette and prism 124 (step 1004). For example, referring to the schematic diagram of FIG. 2B, an AC pump flows anticoagulant from AC bag 114 into AC tubing 110, then through tubing connector 106, along inlet tubing 108, and into and through integrated cuvette and prism 124. In some examples, integrated cuvette and prism 124 may be attached to the inlet tubing downstream of the tubing connector and upstream of the soft cassette. When connected to apheresis system 100, integrated cuvette and prism 124 is positioned upstream of other pumps. Integrated cuvette and prism 124 is positioned adjacent to refractometer 260, which includes a light source and a sensor.

[0067] Next, the method 1000 operates the refractometer 260 with the anticoagulant present in the chamber of the integrated cuvette and prism 124 (step 1008). In some examples, the refractometer 260 is operated with the anticoagulant passing through the integrated cuvette and prism 124 from one end to the other. In some examples, the flow may be stopped when the anticoagulant fills the interior chamber of the integrated cuvette and prism 124. Operating the refractometer 260 includes emitting 420 nm light from a light source in a direction toward the integrated cuvette and prism 124, more specifically, through the integrated prism and onto the anticoagulant contained therein.

[0068] Method 1000 continues by reflecting the emitted light from the prism sensing surface and receiving the reflected light at a sensor of refractometer 260 (step 1012). The sensor corresponds to a CCD or other imaging sensor having a pixel array or light-sensitive area. When light is emitted by the light source, the sensor detects the reflected light on one or more pixels, pixel areas, and / or pixel locations.

[0069] Based on the reflected light detected by a range of pixels in the sensor's pixel array, the controller determines an associated light intensity pattern for the sensor's pixel array (step 1016). This light intensity corresponds to a calibration standard used to determine plasma protein levels from whole blood, as described herein. Method 1000 then selects the light intensities corresponding to one or more pixel locations as calibration standards to be used in future measurements (step 1020).

[0070] 11 is a flow diagram of a method 1100 for determining protein levels in whole blood obtained from a donor 102 while the donor 102 is connected to an apheresis system 100, according to an embodiment of the present disclosure. Method 1100 may correspond to step 928 described in connection with FIG. 9. FIG. 11 illustrates the general order of steps in method 1100. Generally, method 1100 begins with step 1104 and ends with step 1124. Method 1100 may include more or fewer steps, or the steps may be ordered differently than shown in FIG. 11. Method 1100 may be executed by a computer system, controller, processor, centrifuge microcontroller, and / or other device and may be implemented, at least in part, as a set of computer-executable instructions encoded on or stored on a computer-readable medium. In other configurations, method 1100 may be performed, at least in part, by a series of components, circuits, gates, etc., configured in a hardware device, such as, for example, a system-on-chip (SOC), an application-specific integrated circuit (ASIC), and / or a field-programmable gate array (FPGA). Method 1100 will be described below with reference to the systems, devices, valves, pumps, sensors, components, circuits, modules, software, data structures, signal transmission processes, models, environments, apheresis systems, methods, etc., described in connection with FIGS.

[0071] Method 1100 begins with the presence of whole blood in the integrated cuvette and prism 124, with emitted light (e.g., from a light source) reflected from the prism sensing surface and the reflected light received by a sensor of refractometer 260 (step 1104). When light is emitted by the light source (e.g., at 420 nm), the sensor detects the reflected light on one or more pixels, pixel areas, and / or pixel locations.

[0072] Subsequently, based on the reflected light detected by the pixel array of the sensor (e.g., from the prism sensing surface with whole blood present in the integrated cuvette and prism), method 1100 determines an associated light intensity pattern across the pixel array of the sensor (step 1108). The light intensity pattern corresponds to the measured intensity of light at each row and / or each column of pixels in the pixel array. In some examples, the light intensity is associated with an area of the sensor.

[0073] Next, using the calibration reference value or light intensity associated with the anticoagulant, method 1100 determines the pixel location of the sensor where light is detected (by the sensor) at a predetermined light intensity selected from the anticoagulant calibration reference pixel pattern (step 1112). This pixel location may be referred to herein as the shifted pixel location. Method 1100 uses the magnitude of the pixel location shift for whole blood relative to the calibrator solution to determine the protein content of the plasma.

[0074] Next, method 1100 determines whether the shifted pixel position relative to the calibration pixel position corresponds to a pixel shift that is within a predetermined range (e.g., a lower pixel shift limit and an upper pixel shift limit) for plasma donation eligibility (step 1116). In some examples, the lower pixel shift limit is associated with plasma having a protein level of 6.0 g / dL. The upper limit is associated with the upper pixel shift limit, which corresponds to a plasma protein level of 9.0 g / dL. When the pixel shift is determined to be between (and / or inclusive of) these predetermined lower and upper limits, the plasma protein level of the whole blood is sufficient for plasma donation.

[0075] Subsequently, when the pixel shift is within the predetermined range, method 1100 sends a "start apheresis" command to one or more components of apheresis system 100 to initiate the apheresis procedure (step 1120). In one example, the command causes apheresis system 100 to draw whole blood from donor 102 and separate plasma from the whole blood for collection. This process does not require any additional setup between donor 102 and apheresis system 100.

[0076] Subsequently, if the pixel shift is outside of a predetermined range, method 1100 sends an "alarm" to one or more components of apheresis system 100 that prevents the apheresis procedure from beginning (step 1124). The alarm command may sound an alarm through a speaker, display a visual message on a display device associated with apheresis system 100, and / or a combination thereof. If the pixel shift is outside of a predetermined range, donor 102 is disconnected from disposable tubing set 120, and the entire disposable tubing set 120, including the integrated cuvette and prism 124, is discarded or disposed of.

[0077] Thus, the present disclosure determines the plasma protein content of whole blood by measuring reflected light instead of refracted light. Measuring reflected light has many advantages over measuring refracted light. For example, when refracted light enters whole blood, it is rapidly attenuated by both RBC light scattering and RBC light absorption. Therefore, refracted light is very difficult to measure. Measuring reflected light is not attenuated by either RBC light scattering or RBC light absorption.

[0078] FIG. 12A shows pixel patterns from sensor (e.g., CCD) readings using various concentrations of liquid (simulating whole blood with various plasma protein contents (6.3 g / dL to 9.1 g / dL)). Also shown is an anticoagulant calibration pixel pattern (AC calibration pixel pattern at 2.4 g / dL) according to an example of the present disclosure. The anticoagulant (AC) pixel pattern simulates the pixel pattern of plasma with a protein content of 2.4 g / dL. Once the AC calibration pixel pattern is established for a particular plasma collection procedure, one or more pixel rows (Pc) are selected, and the pixel intensity (Ic) of that pixel row is recorded. As an example, in FIG. 12B, the value selected is 90% of the maximum intensity detected. Whole blood (in this example, with a plasma protein content of 6.3 g / dL) is then introduced into the integrated prism and cuvette. The pixel location (Pwb) exhibiting an intensity equal to Ic is identified. The pixel shift is calculated (Pc-Pwb). This value is represented by horizontal line 270 in Figure 12A. The plasma protein content of the whole blood sample is then calculated using the formula K(Pc-Pwb)+2.4, where K is a proportionality constant inherent to the overall configuration of the integrated cuvette and prism system.

[0079] FIG. 12B is a flow diagram of steps 1204, 1208, 1212, and 1216, expanding on the description of FIG. 12A above and step 1112 of FIG. 11. Step 1112 calls for, for example, after the disposable set is assembled with the refractometer in the apheresis device, a calibration standard (e.g., a calibration pixel pattern) to be established using a solution simulating a known plasma protein content. For example, if anticoagulant is used as the calibration solution, the resulting pixel pattern is known to represent a plasma protein concentration of 2.4 g / dL. After whole blood enters the integrated cuvette in the disposable set, a second pixel pattern representing the plasma protein content of the whole blood is obtained.

[0080] In step 1204, a pixel row (Pc) is selected from the pixel array pattern established using the calibration solution (step 1020) that has a brightness (e.g., light intensity) value (Ic) that is, for example, 90% of maximum brightness. In step 1208, a pixel row (Pwb) is identified from the pixel array pattern established using step 1108 (the pixel pattern from a whole blood sample received in an integrated cuvette) that displays a brightness (e.g., light intensity) equal to Ic from step 1204.

[0081] In step 1212, the pixel shift between Pc and Pwb (e.g., pixel shift = Pc - Pwb) is determined. In step 1216, the protein concentration of the plasma of the whole blood is calculated using the equation K(Pc - Pwb) + C. K is an empirically determined proportionality constant built into the software, with units of g / dL / pixel. K is specific to the optical geometry, prism material, wavelength of the light source, and resolution of the optical sensor (e.g., CCD). Pc - Pwb is the pixel shift value in pixels. C is the plasma protein concentration value, in g / dL, that the calibration solution simulates. For an anticoagulant calibration solution, C = 2.4 g / dL. It should be noted that although step 1204 is described as selecting a 90% brightness (e.g., light intensity) value (Ic), i.e., a single value, multiple Ic values may be selected and the pixel shift analysis described in steps 1212 and 1216 may be performed on each of the selected intensity values. The average of the resulting values (step 1216) may then be used to determine the plasma protein concentration. Methods for determining the proportionality constant K are described later in this disclosure.

[0082] FIG. 12A shows a graph of sensor (e.g., CCD) readings using various concentrations of liquid (simulating whole blood with various plasma protein contents (6.3 g / dL to 9.1 g / dL)). Also shown is an anticoagulant calibration pixel pattern (AC calibration pixel pattern at 2.4 g / dL) according to an example of the present disclosure. The anticoagulant (AC) pixel pattern simulates the pixel pattern of plasma with a protein content of 2.4 g / dL. Once the AC calibration pixel pattern is established for a particular plasma collection procedure, one or more pixel rows (Pc) are selected and the pixel intensity (Ic) of that pixel row is recorded. As an example, in FIG. 12A, the value selected is 90% of the maximum intensity detected. Any other suitable intensity value other than 90%, such as 80% intensity, 85% intensity, etc., may also be used. Alternatively, multiple intensity values may be measured and averaged. Whole blood (in this example, with a plasma protein content of 6.3 g / dL) is then flowed into the integrated prism and cuvette. The pixel location (Pwb) that exhibits an intensity equal to Ic is identified. The pixel shift is calculated (Pc-Pwb). This value is represented by the horizontal line in Figure 12A. The plasma protein content of the whole blood sample is then calculated using the formula K(Pc-Pwb)+2.4, where K is a proportionality constant inherent to the overall configuration of the integrated cuvette and prism system.

[0083] Figure 12C is a flow chart illustrating the steps involved in determining the linear proportionality constant K. Step 1262 in Figure 12C calls for a 90% intensity value, although other values may be selected, e.g., 80%, 60%, etc. Also, an average value of two or more intensity values may be used, such as the average of 90% and 80%.

[0084] 12D-12G show a series of pixel patterns used to determine the proportionality constant K according to steps 1254, 1258, 1262, 1266, 1270, 1274, and 1278 of FIG. 12C.

[0085] In step 1254, a calibration solution simulating a known plasma protein concentration (Cc) is obtained. The calibration solution is placed in a cuvette using an integrated cuvette and prism assembled to the refractometer. A reference pixel pattern is then generated for the calibration solution. In step 1258, a second solution simulating plasma of known protein concentration (Cs) is used to flush the calibration solution from the cuvette, leaving the second solution in the cuvette. A pixel pattern is generated for the second solution.

[0086] In step 1262, the reference pixel pattern is used to identify a pixel row that exhibits, for example, 90% of the maximum brightness (e.g., intensity) in the reference pixel pattern. The row number (Ps) and its brightness (lc) are recorded. In step 1266, the row number (Ps) in the pixel pattern of the second solution that exhibits a brightness equal to lc is identified. In step 1270, a K value is calculated using the following formula: K = (Cc - Cs) / (Pc - Ps), in g / dL / pixel. In step 1274, steps 1254-1270 are repeated for multiple solutions, each simulating plasma of a known but different concentration. In step 1278, the K values obtained from the multiple solutions are averaged, and this average is used to determine the plasma protein concentration of the unknown value.

[0087] In the example shown, an anticoagulant solution simulating a plasma protein concentration of 2.4 g / dL was used to generate the reference calibration pixel pattern. Other solutions simulating known plasma protein contents may be used, such as normal saline. In addition to the calibration pixel pattern, Figure 12D shows a second pixel pattern for a solution simulating a plasma protein content of 6.3 g / dL. A pixel shift associated with a brightness of 50 was selected, indicated by the horizontal arrow connecting the two patterns. Note that the pixel shift associated with the second pixel pattern (relative to the calibration pixel pattern) is equal to 1200 pixels (3000 - 1800 = 1200). From the information contained in Figure 12D, the proportionality constant K can be calculated as (6.3 - 2.4) / 1200 = 0.00325 g / dL / pixel. Figures 12E-12G show repeated calculations of the proportionality constant K using solutions simulating different plasma protein concentrations.

[0088] Figure 13A is a perspective view of an integrated cuvette and prism substrate (124 and Figure 4) of a disposable tubing set 120 according to an embodiment of the present disclosure. Figure 13B shows a view of the prism substrate assembled to the cuvette 124 shown in Figure 13A. The prism may be secured to the cuvette 124 in any suitable manner, such as with any suitable adhesive. The prism and cuvette 124 may be configured such that the prism is mechanically coupled to the cuvette 124.

[0089] 14A and 14B illustrate an exemplary refractometer 1410 according to the present disclosure, showing the contact points between the disposable cuvette and the prism 124. The refractometer 1410 includes a light source 1412 and a camera 1414. The descriptions of the light source and camera of the refractometer 260 above also apply to the light source 1412 and the camera 1414.

[0090] Cuvettes (with associated tubing) are loaded into tray 1420 and then raised into position below the refractometer. The prism is positioned above the flow path, allowing gravity to pull the cells away from the sensing surface, thus allowing the pure plasma layer to be measured without prior cell removal. A permanently mounted 90-degree prism 1430 directs the reflected light path toward the CCD / camera 1414. The prism is positioned approximately parallel to the light source 1412. This allows for a more ergonomic layout, so that the optical components do not interfere with operator movement. A positioning mechanism 1440 facilitates accurate and consistent positioning of the cuvettes and prism within the instrument.

[0091] The pixel shifting method of the present disclosure advantageously improves the accuracy of plasma protein content measurements. For example, by using the pixel shifting method, loading variations that may occur when loading cuvettes into a refractometer are not an issue. Furthermore, the pixel shifting method accounts for dimensional differences that may exist between various different disposable cuvettes, allowing the use of disposable cuvettes.

[0092] Thus, the present disclosure provides a method for measuring plasma protein content with a disposable cuvette. The integration of the prism and cuvette into a disposable item allows protein measurements to be made without an open blood event and the associated risk of infection or contamination. This approach also allows for repeated measurements throughout the apheresis procedure, if desired.

[0093] A drawback of disposable cuvettes and prisms is that expensive optical components such as glass prisms must be converted to designs that are easier and cheaper to manufacture, likely resulting in the use of plastic components, and the disposable items become part of the optical path of the instrument, which would normally require precise alignment to accommodate reading and loading operations between different individual cuvettes.

[0094] The present invention addresses these shortcomings by using a calibration fluid (anticoagulant) and pixel shifting technique. When a disposable cuvette is loaded into the sensor and AC fluid is present, a pixel pattern appears on the CCD due to reflected light. However, the pattern will have slight positional errors from run to run due to small deviations in the cuvette loading position or small differences in optical clarity between different prisms. These differences typically result in measurement errors.

[0095] The present pixel shift method is robust to these errors by using only the pattern shift (rather than the absolute position) between the calibration fluid pixel pattern and the blood pixel pattern that requires measurement. By measuring only the amount of pixel shift, the device is robust to the specific location of the pixel pattern.

[0096] The present disclosure generally measures plasma protein content based on a linear correlation between lateral pixel shifts in a refractometer pixel pattern produced by samples of anticoagulant calibration solutions and whole blood and protein concentration. Additionally, the teachings herein relate to the use of a light spectrum (420 nm) that reduces errors associated with refracted light being reflected by red blood cells onto the refractometer's optical sensor.

[0097] Any of the steps, functions, and operations described herein may be performed continuously and automatically.

[0098] Although the flowcharts have been discussed and illustrated with respect to a particular sequence of events, it should be understood that modifications, additions, and omissions can be made to this sequence without substantially affecting the operation of the disclosed embodiments, configurations, and aspects.

[0099] Exemplary systems and methods of the present disclosure have been described in connection with measuring refractive index in an apheresis system. However, to avoid unnecessarily obscuring the present disclosure, the foregoing description omits many known structures and devices. This omission should not be construed as limiting the scope of the disclosure as set forth in the claims. Specific details are set forth to provide an understanding of the present disclosure. However, it should be understood that the present disclosure may be practiced in a variety of ways other than the specific details set forth herein.

[0100] Many variations and modifications of the present disclosure may be employed: some features of the present disclosure may be provided without other features.

[0101] References herein to “one embodiment,” “embodiment,” “exemplary embodiment,” “some embodiments,” etc., mean that the described embodiment may include a particular feature, structure, or characteristic, but not all embodiments necessarily include that particular feature, structure, or characteristic. Moreover, such phrases do not necessarily refer to the same embodiment. Furthermore, it should be noted that when a particular feature, structure, or characteristic is described in connection with one embodiment, the description of such feature, structure, or characteristic may apply to any other embodiment, unless otherwise stated and / or unless it will be readily apparent to one skilled in the art from the detailed description. The present disclosure, in its various embodiments, configurations, and aspects, includes components, methods, processes, systems, and / or apparatus substantially as illustrated and described herein, including various embodiments, subcombinations, and / or subsets thereof. After understanding the present disclosure, those skilled in the art will understand how to make and use the systems and methods disclosed herein. In various embodiments, configurations and / or aspects, the present disclosure includes providing apparatus and processes in the absence of items not shown and / or described herein, or in various embodiments, configurations and / or aspects thereof, including the absence of items that may have been used in previous apparatuses or processes, for example, to improve performance, ease of use, and / or reduce implementation costs.

[0102] The foregoing description of the present disclosure has been provided for purposes of illustration and description. It is not intended to limit the disclosure to the form or forms disclosed herein. For example, in the foregoing Detailed Description, various features of the present disclosure are grouped together in one or more embodiments, configurations, and / or aspects for the purpose of streamlining the disclosure. Features of the embodiments, configurations, or aspects of the present disclosure may be combined in alternative embodiments, configurations, or aspects other than those described above. This method of disclosure is not to be interpreted as reflecting an intention that the claimed disclosure requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment, configuration, or aspect. Accordingly, the following claims are hereby incorporated into this Detailed Description, with each claim standing on its own as a separate preferred embodiment of the present disclosure.

[0103] Furthermore, while the description of the present disclosure includes a description of one or more embodiments, configurations, or aspects, and certain variations and modifications, other variations, combinations, and modifications are within the scope of the present disclosure, e.g., may be within the skill and knowledge of a person skilled in the art after understanding the present disclosure. It is intended to entitle, to the extent permitted, the inclusion of other embodiments, configurations, and / or aspects that include alternative and / or equivalent structures, functions, ranges, or steps in place of those set forth in the claims, regardless of whether such alternative and / or equivalent structures, functions, ranges, or steps are disclosed herein, and without any intention to offer any patentable subject matter to the public.

[0104] An exemplary embodiment includes attaching a disposable tubing set including an integrated cuvette to an apheresis machine; connecting a plasma donor to the disposable tubing set by puncturing the plasma donor's vein with a needle communicating with a tube of the disposable tubing set, allowing whole blood to flow from the plasma donor into the tube of the disposable tubing set; connecting an anticoagulant bag including an anticoagulant to the tube of the disposable tubing set; pumping the anticoagulant from the anticoagulant bag along the tube and into a space within the integrated cuvette; and irradiating the anticoagulant from a light source of a refractometer associated with the apheresis machine through a portion of the integrated cuvette. determining a calibration reference value for the refractometer based on a first light emitted onto a plasma donor and an amount of the first light reflected to a sensor of the refractometer; pumping whole blood from the plasma donor along the tubing into the space within the integrated cuvette; operating the refractometer associated with the apheresis device to emit a second light from the light source of the refractometer through a portion of the integrated cuvette onto the whole blood in the integrated cuvette and reflect the amount of the second light to a sensor of the refractometer; and determining a plasma protein level associated with the whole blood in the integrated cuvette based on the calibration reference value and the amount of the second light reflected to the sensor of the refractometer.

[0105] In one or more of the above aspects, the method includes initiating, via a processor, an apheresis operation of the apheresis device when the plasma protein level associated with the whole blood in the integrated cuvette is within a predetermined range, the apheresis operation separating plasma from the whole blood. In one or more of the above aspects, the predetermined range is greater than or equal to 6.0 g / dL and less than or equal to 9.0 g / dL. In one or more of the above aspects, the integrated cuvette includes an integrated prism formed on at least one surface of the integrated cuvette, and the first light and the second light pass through the integrated prism when emitted and reflected. In one or more of the above aspects, determining the calibration reference value includes determining a light intensity pattern of the emitted first light reflected to the sensor of the refractometer and setting the light intensity pattern measured by the sensor as a calibration reference pixel pattern. In one or more of the above embodiments, determining the plasma protein level associated with the whole blood in the integrated cuvette includes: determining, via the processor, a whole blood light intensity pixel pattern to be compared to the calibration reference pixel pattern; determining, via the processor, a pixel position shift between the whole blood pixel pattern and the calibration reference pixel pattern, the pixel position shift measured between pixels of the same intensity; and determining, via the processor, whether the pixel position shift is within a range of a lower pixel shift limit and an upper pixel shift limit. In one or more of the above embodiments, each of the pixel position shifts between the lower pixel shift limit and the upper pixel shift limit corresponds to a known plasma protein level. In one or more of the above embodiments, at least one of the first light and the second light is emitted at 420 nm. In one or more of the above embodiments, the flow of whole blood is paused to allow red blood cells to settle away from a prism measurement surface by gravity. In one or more of the above embodiments, the light source is a light emitting diode.In one or more of the above embodiments, the sensor is a charge-coupled device. In one or more of the above embodiments, the method further includes, when the pixel position shift is determined to be within the range between the lower pixel shift limit and the upper pixel shift limit, sending, via the processor, a start apheresis command to the apheresis device, causing the apheresis device to draw whole blood from the plasma donor via the disposable tubing set through the integrated cuvette and separate plasma from the drawn whole blood. In one or more of the above embodiments, the method further includes, when the pixel position shift is determined to be outside the range between the lower pixel shift limit and the upper pixel shift limit, sending, via the processor, an alarm message to at least one speaker and display device of the apheresis device and causing the apheresis device to abort the initiation of the apheresis procedure.

[0106] An exemplary embodiment relates to a disposable tubing set including a tubing connector, a donor supply tubing having a first end connected to the tubing connector, an anticoagulant tubing having a first end connected to the tubing connector, an inlet tubing connected to the tubing connector and extending a length from the tubing connector and in fluid communication with the donor supply tubing and the anticoagulant tubing via the tubing connector, and an integrated cuvette attached to the inlet tubing, the integrated cuvette including a body, a chamber disposed inside and within the cuvette in fluid communication with the inlet tubing, and an integrated prism formed from the body and protruding away from the body, wherein an optical path extends from outside the integrated prism and the integrated cuvette to the chamber.

[0107] In one or more of the above aspects, the disposable tubing set is configured to interconnect with the donor at the second end of the donor supply tube, and the disposable tubing set is configured to interconnect with the anticoagulant bag at the second end of the anticoagulant tube.

[0108] An exemplary embodiment includes a method for detecting a blood flow based on: attaching a disposable tubing set including an integrated cuvette to an extracorporeal blood treatment device; fluidly connecting a donor's whole blood to the disposable tubing set; connecting an anticoagulant container including an anticoagulant to a tubing of the disposable tubing set; pumping the anticoagulant from the anticoagulant container along the tubing into a space within the integrated cuvette; first light emitted from a light source of a refractometer associated with the extracorporeal blood treatment device through a portion of the integrated cuvette onto the anticoagulant in the integrated cuvette; and a first pixel pattern of the first light reflected to a sensor of the refractometer. determining a calibration reference value for the refractometer using a calibration standard; pumping whole blood from the donor along the tubing into the space within the integrated cuvette; operating the refractometer associated with the extracorporeal blood treatment device to emit a second light from the light source of the refractometer through a portion of the integrated cuvette onto the whole blood in the integrated cuvette and reflect a portion of the second light to the sensor of the refractometer in a second pixel pattern; and determining a plasma protein level associated with the whole blood in the integrated cuvette based on the calibration reference value and the second pixel pattern.

[0109] In one or more of the above aspects, the calibration reference value corresponds to an anticoagulant calibration pixel pattern. In one or more of the above aspects, determining the plasma protein level associated with the whole blood in the integrated cuvette includes determining a pixel shift between the anticoagulant calibration pixel pattern and a pixel pattern of a fluid of known protein level.

[0110] An exemplary embodiment includes attaching a disposable tubing set including an integrated cuvette to an extracorporeal blood processing device; fluidly connecting whole blood from a donor to the disposable tubing set; connecting an anticoagulant container including an anticoagulant to tubing of the disposable tubing set; pumping the anticoagulant from the anticoagulant container along the tubing into a space within the integrated cuvette; operating a refractometer associated with the extracorporeal blood processing device to emit a first light from a light source of the refractometer through a portion of the integrated cuvette onto the anticoagulant in the integrated cuvette; and measuring an anticoagulant calibration pixel of the anticoagulant corresponding to a reflection of the first light from the anticoagulant. determining a plasma protein pixel pattern for the whole blood corresponding to the reflection of the second light from the whole blood; and determining a plasma protein level associated with the whole blood in the integrated cuvette based on the anticoagulant calibration pixel pattern and the plasma protein pixel pattern.

[0111] In one or more of the above aspects, the anticoagulant calibration pixel pattern corresponds to a pixel pattern of pixel brightness across pixel row numbers of the refractometer sensor, and the sensor includes receiving the first light reflection from the anticoagulant and the second light reflection from the whole blood.

[0112] Any one or more of the above aspects / embodiments substantially as disclosed herein.

[0113] Any one or more of the above aspects / embodiments substantially as disclosed herein may optionally be combined with any one or more of the other aspects / embodiments substantially as disclosed herein.

[0114] One or more means configured to carry out any one or more of the above aspects / embodiments substantially as disclosed herein.

[0115] Any one or more of the foregoing features disclosed herein.

[0116] Any one or more of the foregoing features substantially as disclosed herein.

[0117] Any one or more of the features substantially as disclosed herein may be combined with any one or more of the other features substantially as disclosed herein.

[0118] Combinations of any one of the above aspects / features / embodiments with any one or more of the other aspects / features / embodiments.

[0119] Use of any one or more of the above aspects or features disclosed herein.

[0120] It should be understood that any feature described herein may be claimed in combination with any other feature(s) described herein, regardless of whether the features are from the same described embodiment.

[0121] As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms unless the context clearly dictates otherwise. It will be further understood that as used herein, the terms "include," "including," "includes," "comprise," "comprises," and / or "comprising" specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. The term "and / or" includes any and all combinations of one or more of the associated listed items.

[0122] The term "a" or "an" entity refers to one or more of that entity. Thus, the terms "a" (or "an"), "one or more" (one or more), and "at least one" can be used interchangeably herein. It should also be noted that the terms "comprising," "including," and "having" can be used interchangeably.

[0123] The terms "at least one," "one or more," and "and / or" are open-ended expressions that are both conjunctive and disjunctive in operation. For example, the phrases "at least one of A, B, and C," "at least one of A, B, or C," "one or more of A, B, and C," "one or more of A, B, or C," and "A, B, and / or C" each mean A only, B only, C only, both A and B, both A and C, both B and C, or all of A, B, and C. Where A, B, and C in the above expressions each refer to a single element such as X, Y, and Z, or a class of elements such as X1 to Xn, Y1 to Ym, and Z1 to Zo, the expression is intended to refer to a single element selected from X, Y, and Z, or a combination of elements selected from the same class (e.g., X1 and X2), and a combination of elements selected from two or more classes (e.g., Y1 and Zo).

[0124] As used herein, the term "automatic" and variations thereof refer to any process or operation that occurs (usually continuously or semi-continuously) without material human input as the process or operation is performed. However, a process or operation can be automatic even if the performance of the process or operation uses material or immaterial human input, if that input is received before the performance of the process or operation. Human input is considered material if such input affects how the process or operation is performed. Human input that implies consent to the performance of a process or operation is not considered "material."

[0125] As used herein, the terms "determining," "calculating," and "computing," as well as variations thereof, are used interchangeably and include any type of methodology, process, mathematical operation, or technique.

[0126] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will also be understood that terms as defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the relevant art and this disclosure.

[0127] It should be understood that every maximum numerical limitation given throughout this disclosure is deemed to include, in the alternative, every lower numerical limitation, as if such lower numerical limitations were expressly written herein. Every minimum numerical limitation given throughout this disclosure is deemed to include, in the alternative, every higher numerical limitation, as if such higher numerical limitations were expressly written herein. Every numerical range given throughout this disclosure is deemed to include, in the alternative, every narrower numerical range that falls within such broader numerical range, as if such narrower numerical ranges were all expressly written herein.

Claims

1. 1. A method for determining the plasma protein content of a blood sample using a refractometer including a light source and a light sensor, the method comprising: calibrating the refractometer by identifying a calibration pixel pattern for first pixels of the optical sensor illuminated by light from the light source reflected from a sensing surface of a container containing a reference fluid having a known reference concentration; determining a blood pixel pattern of second pixels of the optical sensor illuminated by light from the light source reflected from the sensing surface when the blood sample is present in the container; determining a pixel shift distance along the optical sensor from the calibration pixel pattern to the blood pixel pattern; determining the plasma protein content of the blood sample based on the pixel shift distance; and the container is connected to an apheresis machine; and operating the apheresis device to separate plasma from the blood sample when the determined plasma protein content is within a predetermined range. Method for determining plasma protein content.

2. 10. The method of claim 1, the container includes a prism having the sensing surface; method.

3. 3. The method of claim 2, determining the plasma protein content of the blood sample is further performed based on the known reference concentration of the reference fluid, the wavelength of light generated by the optical sensor, the resolution of the optical sensor, and the optical properties of the prism. method.

4. 3. The method of claim 2, the refractometer and the prism are positioned above the container so that gravity draws red blood cells of the blood sample away from the sensing surface; method.

5. 10. The method of claim 1, The method further comprises pausing the flow of the blood sample through the container during the step of identifying the blood pixel pattern to allow gravity to pull red blood cells of the blood sample away from the sensing surface of the container. method.

6. 10. The method of claim 1, the reference fluid comprises at least one of an anticoagulant and saline; method.

7. 10. The method of claim 1, the container is a cuvette containing an integrated prism, and the sensing surface is on the integrated prism; method.

8. 8. The method of claim 7, The method is performed by a controller of the apheresis device. method.

9. 8. The method of claim 7, The light from the light source has a wavelength of 275 nm, 375 nm, 420 nm, 370 nm to 470 nm, or 550 nm to 600 nm. method.

10. A system for measuring the plasma protein content of a blood sample, the system comprising: A light source and An optical sensor; a container containing a prism having a sensing surface; a support member configured to hold the container relative to the light source and the light sensor such that light generated by the light source is reflected from the sensing surface to the light sensor; A controller; Equipped with The controller calibrating the system by identifying a calibration pixel pattern of first pixels of the optical sensor illuminated by light from the light source reflected from the sensing surface when a reference fluid having a known reference concentration is present in the container supported by the support member; identifying a blood pixel pattern of second pixels of the optical sensor illuminated by light from the light source reflected from the sensing surface when the blood sample is present in the container; determining a pixel shift distance along the optical sensor from the calibration pixel pattern to the blood pixel pattern; determining the plasma protein content of the blood sample based on the pixel shift distance; Furthermore, an apheresis device is provided, the controller operates the apheresis device to separate plasma from the blood sample when the determined plasma protein content is within a predetermined range. system.

11. 11. The system of claim 10, the controller further determines the plasma protein content of the blood sample based on the known reference concentration of the reference fluid, the wavelength of light produced by the light source, the resolution of the optical sensor, and the optical properties of the prism. system.

12. 11. The system of claim 10, the light source, the light sensor, and the prism are positioned above the container such that gravity draws red blood cells of the blood sample away from the sensing surface; system.

13. 11. The system of claim 10, the reference fluid comprises at least one of an anticoagulant and saline; system.

14. 11. The system of claim 10, The light from the light source has a wavelength in the range of 370 nm to 470 nm. system.

15. 1. An apheresis system, the apheresis system comprising: an apheresis device configured to separate plasma from a blood sample; a refractometer configured to measure the plasma protein content of the blood sample; A controller; Equipped with The refractometer comprises: A light source and An optical sensor; a cuvette containing a prism having a sensing surface; a support member configured to hold the cuvette relative to the light source and the light sensor such that light generated by the light source is reflected from the sensing surface to the light sensor; Preparation, The controller calibrating the refractometer by identifying a calibration pixel pattern of first pixels of the optical sensor illuminated by light from the light source reflected from the sensing surface when a reference fluid having a known reference concentration is present in the cuvette supported by the support member; identifying a blood pixel pattern of second pixels of the optical sensor illuminated by light from the light source reflected from the sensing surface when the blood sample is present in the cuvette; determining a pixel shift distance along the optical sensor from the calibration pixel pattern to the blood pixel pattern; determining the plasma protein content of the blood sample based on the pixel shift distance; and operating the apheresis device to separate plasma from the blood sample when the determined plasma protein content is within a predetermined range. Apheresis system.

16. 16. The apheresis system of claim 15, The controller further determines the plasma protein content of the blood sample based on the known reference concentration of the reference fluid, the wavelength of light generated by the optical sensor, the resolution of the optical sensor, and the optical properties of the prism. Apheresis system.

17. 16. The apheresis system of claim 15, the light source, the light sensor, and the prism are positioned above the cuvette so that gravity draws red blood cells of the blood sample away from the sensing surface; Apheresis system.

18. 16. The apheresis system of claim 15, the controller suspending the flow of the blood sample through the cuvette when the controller identifies the blood pixel pattern. Apheresis system.

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