Separation of platelet concentrates (PC) from buffy coat (BC) using the bottom and top drainage (BAT) system.

By the preparation of platelet concentrates (PC) from buffy coat (BC), the blood component separation may be improved considerably. One can use new bag systems with bottom and top drainage (BAT) which allow partial automation of the separation procedure. Thus, it is possible to produce very pure red cell concentrates (RCC) and FFP, as well as BC, by one separation step under well standardized conditions. Several preparative factors influence the quality of the PCs, especially the storage of the whole blood and the BC. Optimal yields (0.72-0.78 x 10(11) platelets), separation efficiency (67.7-70.8%) and lowest cell contamination (leukocytes 0.1-0.2 x 10(8), red cells 0.2-0.3 x 10(8) per concentrate) were obtained with whole blood stored for 1 h and BC for 2-4 h before resuspension by 30 min face-over-face-rotation. In respect to the release of leukocyte proteases during the storage, the BC should not rest for more than 2-3 h before separation of the platelets in order to prevent potentially functional impairment of the platelets by leukocyte proteases.