Viability and function of platelets frozen at 2 to 3 C per minute with 4 or 5 per cent DMSO and stored at -80 C for 8 months.

Each of 15 healthy male volunteers was treated with 650 mg of aspirin 24 hours before the autologous transfusion of one unit of freeze-preserved platelets. Freeze-thaw-wash recovery values in vitro, viability and function in vivo, and the bleeding time and platelet aggregation response were measured. The platelets were frozen with 4 or 5 per cent dimethylsulfoxide (DMSO) at an overall rate of 2 to 3 C per minute and were stored at -80 C in a mechanical freezer for up to eight months.