Systems for separating platelets from blood in a centrifuge separation device (12) to derive the yield of platelets through tubing branch (30) in real time as processing is accomplished. The systems determine an incremental blood volume processed from tubing branch (20) during a succession of incremental time periods during a separation step. The systems also estimate a separation efficiency for the separation device (12) during each incremental time period, while also estimating a current count of platelets available from a donor through branch (20) during each incremental time period. The systems multiply incremental blood volume for each time period by the estimated current count of platelets and by the estimated separation efficiency, to derive incremental platelet yields.
