[Preliminary results of the 2nd multicenter study. Thrombocytapheresis with the Fresenius AS-104 blood cell separator and ring study of cell counting. Section of Therapeutic and Preparative Hemapheresis of the DGTI].

Only multicenter studies on cell separators give valid data to compare different cell separators. The aim of the 2nd multicenter study was to evaluate the separation protocol, software version V 4.61, of the Fresenius AS-104 cell separator for efficiency and deviation from predicted yields. Plateletpheresis data from twelve hemapheresis centers, using identical apheresis protocols and cell counting methods, were registered and statistically analyzed. Additionally, the counting methods of the centers were controlled by a ring study with biweekly external cell count trials. To get a comparison, the apheresis data, which depend on the center effects, were corrected by the values from the ring study. Preliminary results of 380 runs are 45.2 +/- 8.1% for the separation effectivity, 1.95% deviation from the predicted yield, whereby 90% of all runs deviated less than 20% from the predicted yield. 50% of products had a WBC contamination below 6 x 10(6).