Abstract: A fluid processing system includes a fluid processing device and a fluid flow circuit. The device includes a pump configured to convey a priming fluid through the circuit. The pressure in a conduit of the circuit is measured while the pump is operated at a particular rate. When the magnitude of the pressure is less than the magnitude of a predetermined pressure at the end of a time interval, the pump is operated at an increased rate. When the magnitude of the pressure is greater than the magnitude of the predetermined pressure at the end of the time interval, the pump is instead operated at a decreased rate. The magnitude of the pressure in the conduit is again compared to the magnitude of the predetermined pressure after the pump has operated at the increased or decreased rate for the time interval to determine how to next adjust the operational rate.

Abstract: A method and device are provided for centrifugally separating plasma from whole blood in which whole blood is introduced into a flow circuit having a blood access device connected to a first tubing for drawing whole blood from a blood source and for flowing whole blood to a centrifugal separation chamber; a volume of saline is added to the whole blood as it flows through the first tubing to dilute the whole blood; the volume of saline added to the whole blood is tracked; the whole blood having the volume of saline added thereto is separated in the centrifugal separation chamber so that an interface is created between the plasma and added saline and the cellular components of the whole blood; the separated plasma and added saline is flowed from the centrifugal separation chamber to a collection container; and a volume for the plasma and added saline in the collection container is determined.