Leukocyte-depleted platelets prepared from pooled buffy coat post-transfusion increment and "in vitro bleeding time"...

A technique for preparation of platelet concentrate (PC) from pooled buffy coat (BC) is described in this study. The yield of platelets from 4 BCs was 310+/-48x10 9 per unit with a leukocyte content of 21+/-20x10 6 per unit. When a leukocyte removing filter was interconnected, Sepacell 5N and Pall PL-50 filters, no leukocytes could be found in 56 of 59 and in 36 of 37 PCs, with a maximum content of 2.3 and 0.54x10 6 leukocytes per PC, respectively. The platelet yield was 276+/-37 and 279+/-54x10 9 per unit, respectively. The in vitro bleeding time (IVBT), using the Thrombostat 4000/2, corresponded with the corrected count increment in most of 11 thrombocytopenic patients receiving platelet transfusions. However, in two transfusions no correction of IVBT was obtained. This technique offers a new possibility to investigate the functional capacity of transfused platelets.