[A new multiple blood bag system with top and bottom drainage. Comparison with the conventional multiple bag system]

Blood components were investigated following manual preparation in a conventional 4-bag system (A) or automatic preparation in a top and bottom system (B). To overcome inter donor differences two units of whole blood were pooled and subsequently split up into the original bags. Leukocyte-poor platelet concentrates (PC) were manufactured from both types of buffy-coat (A and B). The volumes of the various blood components were similar, whereas the residual leukocytes and platelets in the red cell concentrates from the top and bottom system were significantly lower (p less than 0.01). Both types of PC contained less than 10(7) leukocytes and could be stored for 7 days maintaining a pH above 6.5. We conclude that the top and bottom system enables automatic preparation of red cell concentrates and plasma with a significantly better buffy-coat removal than with manual processing.