A centrifugal blood processing apparatus comprising a centrifuge rotor, a separation chamber, a tubing set for conducting blood components and fluids and a method for controlling the blood processing apparatus comprising separating a blood component in a separation chamber flowing the blood component out of the separation chamber and into a concentration chamber concentrating the blood component in the concentration chamber and flushing the blood component out of the concentration chamber. The method further comprising simultaneously flowing a solution, such as a wash solution or PAS, into the concentration chamber between the separation chamber and the concentration chamber.
