Systems and methods for real time calibration of pump stroke volumes during a blood separation procedure

In a blood separation procedure having sequentially-performed draw and return phases including at least a first and a second draw phase separated by a first return phase, the procedure utilizing a tubing set comprising a tubing through which fluid is flowed and a reusable hardware component comprising at least one pump having a stroke volume, a rotational rate, and an inlet through which fluid is flowed by operation of the pump and a programmable controller for automatically performing the fluid processing procedure, wherein the controller is programmed with first and second continuous functions defining a relationship between pump inlet pressure and pump stroke volume for each of the draw phase and the return phase, and the controller controls the separation procedure based at least in part on a fluid flow rate through the pump, the fluid flow rate being a product of the pump stroke volume and the pump rotational rate, a method for real time calibration of the pump stroke volume to achieve a target fluid flow rate comprising:

• a) commencing the first draw phase of the blood separation procedure to operate the pump to draw blood through the tubing;
• b) measuring fluid pressure in the tubing at the inlet of the pump;
• c) calculating a current pump stroke volume and pump rotational rate for the first draw phase with the controller based on the continuous function for the draw phase and the pump rotational rate;
• d) determining an adjusted pump rotational rate utilized by the controller to control the procedure to achieve the target fluid flow rate;
• e) conforming the pump rotational rate to the adjusted pump rotational rate;
• f) upon completion of the first draw phase, commencing the first return phase;
• and
• g) upon completion of the first return phase, commencing the second draw phase.