Preparation and storage of platelet concentrates

A technique of platelet concentrate preparation and storage is presented which permits the maximum number of viable and functional platelets to be preserved for periods of 72 hours. Although the storage conditions must be followed precisely, the method is nevertheless simple to perform and does not require specialized expensive equipment. Critical factors include: 1) preparation of the platelet concentrates with an initial centrifugation of 1000 X g for 9 minutes and a second centrifugation of 3000 X g for 20 minutes (86% +/- 1 platelet yield), 2) a storage bag composed of either Fenwal's PL-146 or McGaw plastic, 3) constant gentle mixing, 4) a 70 ml residual plasma volume, and 5) room temperature storage (22 C +/- 2). In Vivo platelet recovery after 72 hours of storage at room temperature averaged 46 per cent +/- 3 and survival was 7.9 days +/- 0.3 (81% of fresh platelet viability). The function of these platelets as measured by the correlation between bleeding time and platelet count after transfusion of pooled platelets into unimmunized, aplastic thrombocytopenic recipients was as good as that of fresh platelets. Both viability and function of concentrated platelets stored at 4 C are severely compromised.