Improved viability of previously frozen platelets.

The main feature of this new approach to platelet freezing is a controlled rate of addition and postthaw removal of 5% dimethylsulfoxide (DMSO). When DMSO was removed from fresh nonfrozen platelet concentrates before transfusion, no adverse effect on posttransfusion survival was observed. The 51Cr recovery of autologous fresh platelet concentrates in vivo was 65% ± 5%, while that of autologous platelets previously frozen with DMSO and washed prior to transfusion was 47% ± 3%. The lifespan values were similar for fresh platelets and previously frozen washed platelet concentrates. When approximately 95% of the DMSO was removed from previously frozen washed platelets before transfusion, the 51Cr recovery was about 70% of the value for fresh platelet concentrates, and the lifespan value was similar to that of fresh platelet concentrates. No adverse side effects were observed. The hemostatic effectiveness of these platelets has yet to be studied.