[Second multicenter study of thrombocytapheresis using the Fresenius AS104 blood cell separator and ring study for quality control of cell counts. Members of the Preparative and Therapeutic Hemapheresis Section of DGTI].

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 separation efficiency, WBC contamination and yield's deviation from prediction. Plateletpheresis data from 12 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 cell counts. To get a comparison the apheresis data, which were dependent of the center effects, were corrected by the systematical deviation found in the quality control from the ring study. The results of 935 runs are 47.3 +/- 8.1% for the separation effectivity. 7.2% median deviation from predicted yield, whereby 90% of all runs deviated less than +/- 22% from predicted yields. 50% of products had a WBC contamination below 6 x 10(6), 99% below 5 x 10(7).