Factors influencing yield of plateletpheresis by discontinuous centrifugation.

Plateletphereses performed by the Haemonetics Model 30 Blood Processor under a fixed condition were retrospectively analyzed. The mean platelet yield was 5.97 X l0 (ll) (+/- l.46 X l0 (ll). Prepheresis platelet count was significantly correlated to platelet yield (p less than 0.001), but hematocrit was not (p greater than 0.1). Blood-drawing time showed a significant correlation (p less than 0.01) and may suggest than an infusion rate of 60 ml/minute is a technique of choice. A large number of platelets (% platelet recovery = 73.0 +/- l4.l%) was discarded in order to remove erythrocytes and leukocytes from the initial product. The recovery was negatively correlated to the percentage removal of leukocytes (p less than 0.01), which means that a platelet product of good quality not containing leukocytes can be prepared at the sacrifice of a large quantity of platelets. It is desirable to devise a simple and practical technique to obtain pure platelets without loss.