System and method for keeping blood plasma anticoagulant concentration constant

Abstract

To provide a method and a system for achieving a consistent plasma anticoagulant ratio for a plasma product in plasma exchange processing.SOLUTION: There is provided a method for executing plasma exchange using a plasma separation system including a fluid flow circuit, a plasma separator, and a control unit. The method includes inputting a hematocrit value of a donor, setting a desired plasma anticoagulant ratio for a plasma product, calculating an initial ratio of an anticoagulant to whole blood (ACR), and executing separation by the separation system. The system also includes a programmable control unit having a screen for receiving an input from an operator, which is configured to give the initial ACR on the basis of the input from the operator, and activate the system on the basis of the initial ACR.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] [Cross - Reference to Related Applications] This application claims the benefit of priority of U.S. Provisional Patent Application No. 63 / 458,759, filed on April 12, 2023, the content of which is incorporated herein by reference.

[0002] [Technical Field] This application relates to systems and methods for performing plasmapheresis, and more particularly, to plasmapheresis systems and methods in which plasma products contain a certain proportion of plasma anticoagulants.

Background Art

[0003] The plasmapheresis method is a component separation method in which whole blood is collected from a donor, the plasma is separated from and retained from the cellular blood components (red blood cells, platelets, white blood cells), and the cellular blood components are returned to the donor. The separation of plasma and cellular components is usually performed by an automated procedure using centrifugation or membrane filtration.

[0004] In an automated plasmapheresis method, whole blood is collected from a donor, mixed with an anticoagulant ( "ACR") at a specified ratio, and then separated into anticoagulated plasma and red blood cells and other cellular components.

[0005] Methods for determining the volume of source plasma that can be collected from a particular donor while maintaining donor safety and comfort typically involve estimating / determining the donor's total blood volume using donor - specific characteristics and then determining the total volume of source plasma that can be collected from that donor. See, for example, WO2019 / 226654 filed on October 23, 2020 and U.S. Patent Application No. USSN17 / 078,824. Both are incorporated herein by reference and disclose systems and methods for optimizing plasma collection volume based on determining the target collection volume of a donor's source plasma using donor - specific characteristics.

[0006] The plasma anticoagulant rate in plasma products can vary based on donor characteristics and the mixing ratio of whole blood and anticoagulant.

[0007] In a plasma exchange process, a plasma exchange device typically mixes the collected whole blood and an anticoagulant at a certain set ratio (ACR), for example, 7:1 to 16:1. The anticoagulant is mixed with the whole blood. When the cellular contents are separated, some anticoagulant remains in the plasma portion of the whole blood. The relative ratio of the anticoagulant to the plasma is not constant and varies based on the ratio of the cellular content to the plasma and on the donor's hematocrit, which may depend on the donor's physical characteristics. Therefore, the final ratio of the anticoagulant in the plasma product to the plasma may vary based on the donor's characteristics and the mixing ratio (ACR) of the whole blood and the anticoagulant.

[0008] Fluctuations in the amount of anticoagulant in the collected plasma can affect the quality of the plasma because if the concentration of the anticoagulant is high, the plasma is diluted, and if the concentration of the anticoagulant is low, clotting or aggregation may occur. The anticoagulant is also known to affect the quality of the collected platelets during storage. Therefore, when the fluctuations in the anticoagulant in the plasma are reduced, the fluctuations in the quality of the stored products in the platelet storage medium should also be reduced.

[0009] Therefore, it is desirable to keep the plasma anticoagulant ratio in the product constant and ensure it. The present application provides a method and a system for achieving a consistent plasma anticoagulant ratio for plasma products in a plasma exchange procedure. SUMMARY OF THE INVENTION

[0010] The present application has several aspects. In a first aspect, a method of performing plasma exchange using a blood separation system including a fluid circuit, a blood separator, and a control unit is provided. The method includes entering a first hematocrit value of a donor, setting a desired plasma anticoagulant ratio for the plasma product, calculating an initial ratio (ACR) of the anticoagulant to the whole blood, and performing separation using the separation system at the initial ACR.

[0011] In a second aspect, an automated system for separating plasma from whole blood comprises a disposable fluid flow circuit including a separator for separating whole blood into a plasma product and a concentrated cell product, and a reusable hardware component including a display unit for receiving input from an operator, a programmable control unit configured to provide an initial ACR based on the operator input and to operate the system at the initial ACR.

[0012] Other aspects will be apparent from the following description and the accompanying drawings.

Brief Description of the Drawings

[0013] FIG. 1 is a perspective view of an exemplary plasmapheresis device suitable for use in the system and method of the present application.

[0014] FIG. 2 is a perspective view of a type of rotary membrane separator incorporated in a disposable set that can be used in the plasmapheresis system of FIG. 1, with a portion cut away to show details.

[0015] FIG. 3 is a perspective view of the front panel of the plasmapheresis system of FIG. 1, showing the components of the disposable set attached thereto.

[0016] FIG. 4 is a schematic diagram showing the operation of the plasmapheresis system in the collection phase.

[0017] FIG. 5 is a schematic diagram showing the operation of the plasmapheresis system in the reinfusion phase.

[0018] FIG. 6 is a flowchart showing the steps of the method according to the present application.

Modes for Carrying Out the Invention

[0019] A more detailed description of the systems and methods according to the present disclosure is provided below. It should be understood that the following description of specific devices and methods is for illustrative purposes only and does not cover all possible variations or applications. Accordingly, the scope of the disclosure is not intended to be limiting and should be understood to encompass variations or embodiments that would occur to those skilled in the art.

[0020] In the context of this application, plasmapheresis is performed in an automated system that includes hardware components generally indicated by reference numeral 10 and a disposable set generally indicated by reference numeral 12 for collecting plasma. Referring to FIGS. 1 - 5 and as described in more detail below, the disposable set 12 is composed of an integrally connected separator, container, and tubes for transporting blood and solutions within a sterile fluid path.

[0021] As shown in FIG. 2, the separator 14 includes a rotary membrane filter 16 attached to a rotor 18 that rotates within a case 20 to separate blood into components. A detailed description of the rotary membrane separator is provided in Shaindleffer's U.S. Patent No. 5,194,145, which is incorporated herein by reference. As will be appreciated, in different systems, separation of whole blood may be achieved by other separation means such as centrifugation, as described in Williamson et al.'s U.S. Patent No. 5,360,542.

[0022] During plasmapheresis, whole blood is drawn from a donor, an anticoagulant is added, and the anticoagulated whole blood enters the separator 14 from the whole blood input port 22. Plasma is separated by the rotary membrane filter and enters the plasma collection container 28 through the plasma line 26 from the plasma output port 24. The concentrated cells are sent from the concentrated cell output port 30 to a reservoir 32 and remain there until reinjected into the donor. As will be appreciated, a portion of the anticoagulant added to the whole blood remains in the separated plasma, and another amount of anticoagulant remains in the concentrated cells.

[0023] The disposable set 12 includes a tube line (donor line 34 ending with a venipuncture needle 36) for introducing whole blood from the donor into the system during collection and returning concentrated cells to the donor during reinfusion, a tube line (blood line 38) for transporting anticoagulated whole blood to the separator, a tube line (cell line 40) for transporting concentrated cells to the reservoir, a tube line (reinjection line 42) for transporting concentrated cells from the reservoir to the donor line, a tube line (plasma line 44) for transporting plasma to the plasma collection container, a tube line (saline line 46) for transporting saline, and a tube line (AC line 48) for transporting an anticoagulant.

[0024] The hardware components 10 include a programmable control unit 50 configured to control the operation of the system. The control unit 50 may be provided as a computer or a related programmable microprocessor or other known mechanism for controlling one or more elements of the system and processing information from one or more elements of the system according to the procedures and steps described herein.

[0025] The control unit 50 is coupled to one or more structures of the hardware components 10 and can, for example, receive information (e.g., in the form of signals) from these structures or provide commands (e.g., in the form of signals) to these structures to control the operation of the structures. The control unit 50 is connected to pumps, drives, or separators and can provide commands to these devices to control their operation. The control unit 50 may be directly electrically connected and coupled to these structures for connection thereto, or the control unit 50 may be directly connected to other intermediate devices that are directly connected and coupled to these structures. The control unit can also be wirelessly connected to any of these devices.

[0026] The control unit may be connected to at least one input unit. The at least one input unit 52 may include a number of different devices according to the embodiments described herein. The input unit provides a communication mode from the operator to the device and from the device to the operator. For example, the input unit 52 includes a keyboard, a keypad, or a touch screen through which a user can give information and instructions to the control unit 50. When the input unit is a touch screen, the touch screen may be a graphical user interface ("GUI") for the operator to control the procedure. For example, in the GUI, a donor ID, donor gender, donor height, donor weight, donor age, donor hematocrit / hemoglobin, target saline infusion volume (when the saline protocol is selected), target plasma volume, and target plasma anticoagulant rate of the plasma product can be input. The input unit 52 also allows the operator to collect status information and process error states. The input unit 52 may also include readers and scanners such as barcode readers, scanners, RFID readers, etc. The input unit / touch screen assembly may be in one of the aforementioned structures to which the control unit 50 is coupled, the control unit 50 receives information, and the control unit 50 provides commands. According to still other embodiments, the input unit 52 may be in the form of a computer device that enables the blood collection system including the control unit 50 to communicate with other systems via a local network (such as via wire, cable, or wirelessly) or communicate with other cell processing systems or other computer devices (such as servers) via a local network, a wide area network, or the Internet. According to such embodiments, the input unit 52 may include an internal transmitter / receiver device.

[0027] Using the input unit 52, a phlebotomist or operator can input parameters and information related to the plasma exchange procedure. This information includes patient measurements such as height, weight, hematocrit value, or characteristics such as gender, reaction to previous blood donations, or other relevant information. The information may also include the required product composition, such as the plasma anticoagulant product ratio. These measurements can be input at the start and during the procedure. The control unit may use these adjustments to calculate characteristics of blood collection, such as the initial ACR value or the second or final ACR value. These set values can be calculated from the input of the phlebotomist or operator and the patient's characteristics. Therefore, although specific components of the system are described herein as performing specific functions, it should be understood that those components are controlled by the control unit to perform those functions. The control unit can also be connected to a patient monitoring device. Before, during, and after the procedure, the control unit receives readings from the patient monitoring device and processes this information before displaying information related to the patient or blood collection.

[0028] On the front panel of the hardware component 10, a plurality of peristaltic pumps (three are shown), including an AC pump 54, a blood pump 56, and a cell pump 58, are arranged. When whole blood from the donor enters the set, the AC pump 54 pumps the anticoagulant solution (AC) into the blood line 38 at a controlled speed. The blood pump 56 sends the anticoagulated whole blood to the separator during the collection stage of the procedure and returns the concentrated cell components and, optionally, replacement fluid to the donor during the reinfusion stage of the procedure. The cell pump 58 sends the concentrated cell components from the separator 14 to the reservoir during the collection stage.

[0029] The front panel also includes a plurality of clamps (four are shown) to which the disposable set 12 can be attached, including a reinfusion clamp 60, a blood clamp 62, a saline clamp 64, and a plasma clamp 66. The reinfusion clamp 60 closes during the collection phase (Figure 4) to occlude the reinfusion line (42) and opens during the reinfusion phase (Figure 5) to allow the blood pump to reinfuse the concentrated cellular components from the reservoir 32 into the donor. The blood clamp 62 opens during the collection phase to allow the anticoagulated whole blood to be fed into the separator 14 and closes during the reinfusion phase to occlude the blood line 38. The saline clamp 64 closes during the collection phase and during the reinfusion of the separated cellular components to occlude the saline line 46. When saline is used as the replacement fluid, the saline clamp 64 opens during the reinfusion phase. The plasma clamp 66 opens during the collection phase to allow plasma to flow into the plasma collection container 28 and closes during the reinfusion phase.

[0030] The hardware components 10 include one or more (e.g., three as shown) weighing scales for monitoring the current plasma collection volume (scale 68), the AC solution volume (scale 70), and the concentrated cell content volume (scale 72). The system also includes various sensors and detectors such as a venous pressure sensor 74, a separator pressure sensor 76, an optical blood detector 78, and an air detector 80.

[0031] The donor remains connected to the system throughout the procedure. As shown, the disposable set 12 includes a single venipuncture needle 36 through which whole blood is drawn from the donor during the collection phase (Figure 4) and concentrated cells are returned to the donor during the reinfusion phase (Figure 5). As described above, the plasmapheresis procedure can consist of multiple cycles, each having a collection / separation phase followed by a return or reinfusion phase. During the collection phase, whole blood is separated into plasma and concentrated cells. The disposable set includes a plasma collection container 28 for containing the separated plasma and a reservoir 32 for containing the concentrated cells. During the reinfusion phase, the concentrated cells from the reservoir 32 are reinfused into the donor through the venipuncture needle 36. Typically, plasmapheresis performed using a single venipuncture needle 36 includes multiple cycles of collection and reinfusion.

[0032] Returning to Figure 4, during the collection phase, an anticoagulant solution (AC) is pumped at a specified set rate and mixed with whole blood as it enters the disposable set 12. The anticoagulated blood is sent to a separator 14 where the plasma is separated from the cellular components and sent to the plasma collection container 28.

[0033] The cellular components are pumped from the separator 14 to the reservoir 32. The collection phase stops when the reservoir 32 reaches the expected concentrated cell volume or when the target plasma collection volume is achieved.

[0034] Next, the reinfusion phase begins. Referring to Figure 5, during the reinfusion phase, the blood pump 56 reverses direction and returns the concentrated cells from the reservoir 32 through the component collection needle 36 to the donor. If a saline protocol is selected to return saline to the donor as a replacement fluid for the collected plasma, saline is infused after the final reinfusion phase.

[0035] Before starting a plasma exchange procedure, donor-specific characteristics can be determined and / or entered into the system to determine at least an appropriate initial anticoagulant / whole blood ratio (ACR) necessary to achieve a desired plasma anticoagulant rate. The plasma anticoagulant rate is the percentage of anticoagulant in the total plasma / anticoagulant product. The plasma anticoagulant rate is a measure of the percentage or concentration of a substance in a solution. The desired plasma anticoagulant rate is set by the user and may be within a set range or value. In one embodiment, the plasma anticoagulant rate is about 7-14%. More specifically, the desired plasma anticoagulant rate is 9-12%. The plasma anticoagulant rate can be set to any value within this range, such as 9.75, 10.1, etc.

[0036] Donor-specific characteristics used to determine the anticoagulant / whole blood ratio (ACR) include at least the donor's hematocrit. This is because hematocrit is required to determine the percentage of anticoagulant collected with the plasma in the plasma product container. Hematocrit (HCT) can also be used to calculate an appropriate ACR based on the desired plasma anticoagulant rate. The percentage of anticoagulant in the plasma / anticoagulant product (divided by 100) is equal to 1 / (1 + ACR × (1 - HCT / 100)). For example, if a plasma anticoagulant rate of 16% is desired and the donor's hematocrit is 38, the calculation is as follows. 0.16 = 1 / (1 + ACR(1 - 0.38)) ACR = 8.5 However, if the donor's hematocrit is 55 and a plasma anticoagulant rate of 16% is still desired, the calculation is as follows. 0.16 = 1 / (1 + ACR(1 - 0.55)) ACR = 11.7

[0037] The donor's hematocrit can be measured using any number of well-known methods, such as the use of a dedicated hematocrit centrifuge (e.g., SciLogex DM4124 hematocrit centrifuge) or a blood analyzer (e.g., Sysmex XP-300(TM) automated blood analyzer). Once determined, the initial ACR can be calculated and set for the procedure.

[0038] The donor's hematocrit value may change during the plasma exchange procedure depending on the amount of plasma collected. Specifically, as the procedure progresses, the amount of the donor's plasma decreases, so the donor's hematocrit value increases in the latter half of the procedure. Therefore, in order to keep the rate of plasma in the product constant, it is necessary to adjust the ACR during the procedure. Therefore, the ACR based on the donor's initial hematocrit may increase in consideration of the increasing hematocrit. In order to estimate this change during the procedure, donor characteristics such as height and weight can be used to provide an estimate of the change. The change in hematocrit can be estimated by calculating the donor's total blood volume and monitoring the volume of plasma collected.

[0039] The donor's total blood volume can be determined using the donor's weight and height, for example, using the Remence formula. In this formula, the total blood volume is based on the donor's BMI (body mass index) (TBV = 70 / √(BMI / 22)).

[0040] As yet another method, the donor's total blood volume is determined using the donor's weight, height, and gender, for example, using the Nadler equation, and then the donor's hematocrit is applied as described above to determine the donor's total plasma volume and the target volume of plasma to be collected.

[0041] As can be understood, the methods for determining the total blood volume described above are exemplary. Other generally accepted methodologies for determining the donor's total blood volume can also be used, such as the methodology described in US2020 / 0147289, which is incorporated herein by reference.

[0042] If not all of the donor measurements necessary to calculate total blood volume are available, an estimation method can be used. For example, if only the donor's weight and hematocrit value are used as donor-specific characteristics, a three-step nomogram such as the above FDA nomogram can be employed. In this nomogram, three different weight classes of donors (between 110 pounds and 149 pounds, between 150 pounds and 174 pounds, 175 pounds and above) are used.

[0043] Next, the total blood volume can be used to determine the donor's second or final hematocrit. For example, if the donor's total blood volume is determined to be 5000 mL and the donor's hematocrit at the start of the procedure is 40%, the red blood cells will be 2000 mL and the plasma will be 3000 mL. After 500 mL of plasma is collected and the associated red blood cells are reinfused into the donor, the donor's total blood volume becomes 4500 mL, of which 2000 mL is red blood cells and 2500 mL is plasma, and the hematocrit is 44.4% (2000 mL / (2000 mL + 2500 mL)), and the hematocrit increases by 4.4%. As another example, for the same donor with a total blood volume of 5000 mL, if 500 mL of plasma is collected and the associated red blood cells are reinfused into the donor together with 50 mL of anticoagulant, the donor's total blood volume becomes 4550 mL, the red blood cells are 2000 mL, and the hematocrit is 43.9% (2000 mL / 4550 mL), an increase of 3.9%. The increase in hematocrit depends on the size of the donor (larger donors have a larger total blood volume and, as a result, a larger total plasma volume, so the change in hematocrit is less) and the amount of plasma collected. Due to the increase in hematocrit, it is necessary to adjust the appropriate ACR. Therefore, based on the target plasma collection volume, the donor's "final" or second hematocrit can be estimated, which will be higher than the initial hematocrit. Using these values, the initial ACR and the second or final ACR can be generated. Alternatively, the hematocrit for the entire procedure may be based on the average of the donor's initial and final hematocrits and the average value used when determining the ACR for the procedure (average ACR).

[0044] Alternatively, the hematocrit may be measured before the start of the procedure for the initial hematocrit and at a later point after the procedure for the final hematocrit or the second hematocrit. The latter point may be during the procedure or at another specified point. This time can be determined based on the volume of the plasma product (given by the scale 68 of the plasma product) or based on the time when a certain volume of plasma has been collected. When calculating the second hematocrit as a measured value rather than an approximation, it is necessary to input the second hematocrit value into the input unit 52. The control unit may prompt the user to input the second hematocrit at a specified point in the procedure, such as at an intermediate point or when the plasma product container reaches a specific volume.

[0045] Donor-specific characteristics can be input by the operator into the control unit using the input unit 52. Alternatively, donor-specific characteristics may be provided to the control unit through a data management system including a database containing such information. When the hematocrit is measured during the treatment, the control unit may be programmed to prompt the user to input the second hematocrit value.

[0046] As can be understood, many of the steps performed to reach the predicted initial ACR, second ACR, or average ACR are pre-programmed into the control unit of the system and can be automatically executed by the operator inputting appropriate donor-specific characteristics and / or receiving feedback from the system such as the volume or weight of the plasma product container.

[0047] The steps of the method disclosed in this specification are shown by the flowchart including FIG. 6 of this application. Referring to FIG. 6, this method includes a first step (box 90) of inputting the donor's hematocrit, a second step (box 91) of setting the desired plasma anticoagulant rate of the product, a third step (box 92) of calculating the initial anticoagulant-to-whole blood ratio (ACR), and a fourth step (box 93) of performing separation using the separation system at the first ACR. According to this method, each step shown in boxes 90-92 is performed before connecting the donor to the fluid flow circuit. When the hematocrit is measured and input to the control unit, and the desired plasma anticoagulant rate is input by the operator or the data management system, the control unit can automatically execute and make a recommendation regarding the ACR used in the procedure, and the first and second ACRs may be used. The second ACR can be estimated by the control unit based on monitoring the total blood volume and the volume of the product known from the donor characteristics, or can be calculated based on the second measured hematocrit value of the donor.

[0048] It will be understood that the described embodiments illustrate some applications of the principles of the present invention. Those skilled in the art can make numerous changes without departing from the spirit and scope of the claimed subject matter, including combinations of features individually disclosed or claimed herein. For these reasons, the claims are not limited to the above description and are set forth in the following claims.

[0049] Aspect Aspect 1. A method for performing plasma exchange using a blood separation system including a fluid flow circuit, a blood separator, and a control unit, the method comprising inputting a value of a first hematocrit of a donor, setting a desired plasma anticoagulant rate for a plasma product, calculating a ratio of an initial anticoagulant to whole blood (ACR), and performing separation using the separation system at the initial ACR.

[0050] Aspect 2. The method of Aspect 1, wherein the first hematocrit value of the donor is measured before the value is input.

[0051] Aspect 3. The calculation of the initial ratio of anticoagulant to whole blood is performed using the formula: (PA% / 100) = 1 / (1 + ACR×(1 - Hct / 100)), where PA% is the plasma anticoagulant rate, ACR is the ratio of anticoagulant to whole blood, and Hct is the donor's hematocrit, the method of Aspect 1.

[0052] Aspect 4. The method of Aspect 1, wherein the plasma anticoagulant rate is 7% - 14%.

[0053] Aspect 5. The method of Aspect 4, wherein the plasma anticoagulant rate is 9% - 12%.

[0054] Aspect 6. The method of any of the above aspects, wherein steps a - c are performed before connecting the donor to the system.

[0055] Aspect 7. The method of any of the above aspects, further comprising inputting at least one additional donor characteristic into the hematocrit value.

[0056] Aspect 8. The method of Aspect 7, wherein the at least one additional donor characteristic includes the donor's weight.

[0057] Aspect 9. The method of Aspect 7 or Aspect 8, wherein the at least one additional donor characteristic includes the donor's height.

[0058] Aspect 10. The method of Aspect 7, wherein a second ACR is calculated using the at least one donor characteristic, and the control unit changes the ACR from the initial ACR to the second ACR at the set point of the separation procedure.

[0059] Aspect 11. The method of Aspect 10, wherein the set point is at about half of the procedure.

[0060] Aspect 12. The method of Aspect 10, wherein the set point is at the time of the specified volume of plasma product.

[0061] Aspect 13. The above formula used to calculate the second ACR is the method of Aspect 10, including calculating the total blood volume from the donor's height and weight and calculating the predicted change in the donor's hematocrit.

[0062] Aspect 14. An automated system for separating plasma from whole blood, comprising a disposable fluid flow circuit including a separator for separating whole blood into a plasma fraction and a concentrated cell fraction, and a reusable hardware component including a display unit for receiving input from an operator, configured to provide an initial ACR based on the operator's input and to operate the system at the initial ACR with a programmable control unit.

[0063] Aspect 15. The automated system of Aspect 14, wherein the programmable control unit is configured to calculate a second ACR and operate the system at the second ACR at a set point of the separation procedure.

[0064] Aspect 16. The automated system of Aspect 15, wherein the set point is during the separation procedure.

[0065] Aspect 17. The automated system of Aspect 15, wherein the set point is at a specified plasma product volume.

[0066] Aspect 18. The automated system of Aspect 15, wherein the programmable control unit calculates a second ACR based on at least one donor characteristic.

[0067] Aspect 19. The automated system of Aspect 18, wherein the at least one donor characteristic includes the donor's weight.

[0068] Aspect 20. The automated system of Aspect 18 or Aspect 19, wherein the at least one donor characteristic includes the donor's height.

Claims

1. 1. A method for performing plasma exchange using a blood separation system including a fluid flow circuit, a blood separator, and a controller, comprising: (a) inputting a first hematocrit value of a donor; (b) establishing a desired plasma anticoagulant ratio for the plasma product; (c) calculating the initial anticoagulant to whole blood ratio (ACR); (d) performing separation with the separation system at the initial ACR.

2. The method of claim 1 , wherein the first hematocrit of the donor is measured prior to inputting the value.

3. 2. The method of claim 1, wherein the calculation of the initial anticoagulant to whole blood ratio is performed using the formula: (PA% / 100)=1 / (1+ACR×(1−Hct / 100)), where PA% is the plasma anticoagulant percentage, ACR is the anticoagulant to whole blood ratio, and Hct is the donor's hematocrit.

4. 2. The method of claim 1, wherein the plasma anticoagulant rate is between 7% and 14%.

5. 5. The method of claim 4, wherein the plasma anticoagulant rate is between 9% and 12%.

6. 2. The method of claim 1, wherein steps (a)-(c) are performed prior to connecting the donor to the system.

7. The method of claim 1 , further comprising inputting at least one additional donor characteristic into the hematocrit value.

8. The method of claim 7 , wherein the at least one additional donor characteristic comprises a donor's body weight.

9. The method of claim 7 or claim 8, wherein the at least one additional donor characteristic comprises donor height.

10. 8. The method of claim 7, wherein the at least one donor characteristic is used to calculate a second ACR, and the controller changes the ACR from the initial ACR to the second ACR at a set point during the separation procedure.

11. The method of claim 10 , wherein the set point is approximately halfway through the procedure.

12. 11. The method of claim 10, wherein the set point is a specified plasma product volume time point.

13. 11. The method of claim 10, wherein the formula used to calculate the second ACR includes calculating a total blood volume from the donor's height and weight and calculating a predicted change in the donor's hematocrit.

14. 1. An automated system for separating plasma from whole blood, comprising: a disposable fluid flow circuit including a separator for separating whole blood into a plasma product and an enriched cell fraction; a reusable hardware component having an input for receiving information from an operator, the reusable hardware component including a programmable controller configured to provide an initial ACR and operate the system at the initial ACR based on the operator's input.

15. 15. The automated system of claim 14, wherein the programmable controller is configured to calculate a second ACR and operate the system at the second ACR at a set point of a separation procedure.

16. The automated system of claim 15 , wherein the set point is midway through the separation procedure.

17. 16. The automated system of claim 15, wherein the set point is a point at a specified plasma product volume.

18. The automated system of claim 15 , wherein the programmable controller calculates a second ACR based on at least one donor characteristic.

19. The character transfer system of claim 18 , wherein the at least one donor characteristic includes a body weight of the donor.

20. 20. The automated system of claim 18 or claim 19, wherein the at least one donor characteristic includes a height of the donor.

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