Systems and methods for calibrating pump stroke volumes during a blood separation procedure

In a blood separation procedure comprising one or more of a priming state, a draw state, a separation state and a return state and utilizing a system comprising a fluid circuit with at least one reservoir and a pump for flowing fluid through the fluid circuit during each state, a method for adjusting a pump flow rate for consecutive performances of the same procedure state, comprising:

• a) establishing a minimum volume of fluid to be pumped during the initial performance of a selected first state of the procedure in an amount to account for permissible tolerances;
• b) providing a predetermined value for a flow rate of fluid to or from the reservoir for the selected first state of the procedure;
• c) weighing the reservoir at the beginning of the initial performance of the selected first state of the procedure;
• d) operating the pump to flow fluid to or from the reservoir for the initial performance of the selected first state of the procedure;
• e) weighing the reservoir at the end of the initial performance of the selected first state of the procedure;
• f) comparing the weight of the reservoir at the beginning of the initial performance of the selected first state of the procedure to the weight of the reservoir at the end of the initial performance of the selected first state of the procedure to determine an actual volume of fluid pumped during the initial performance of the selected first state of the procedure and to determine an actual flow rate of fluid to or from the reservoir;
• g) comparing the minimum volume of fluid to be pumped during the initial performance of the selected first state of the procedure to the actual volume of fluid pumped during the initial performance of the selected first state of the procedure;
• h) if the actual volume of fluid pumped during the initial performance of the selected first state of the procedure exceeds the minimum volume of fluid to be pumped, then determining a variance between the actual flow rate and the predetermined value for the flow rate;
• i) calculating a pump volume for the initial performance of the selected first state of the procedure;
• j) adjusting the predetermined value for the flow rate for a subsequent performance of the selected first state of the procedure based on the variance wherein a maximum permissible adjustment of the predetermined value for the flow rate from the initial performance of the selected first state to the subsequent performance of the selected first state is limited to a predetermined amount that is less than the variance between the predetermined value for the flow rate and the actual flow rate;
• and
• k) operating the pump at the predetermined value for the flow rate for the subsequent performance of the selected first state of the procedure to flow fluid to or from the reservoir for the subsequent performance of the same state of the procedure.