Clinical evaluation of the effects of storage time and irradiation on transfused platelets.

Platelet concentrates stored for up to 5 days at room temperature or irradiated with 15 Gy immediately prior to transfusion were evaluated for their ability to increase the platelet count in thrombocytopenic patients. Platelets irradiated with a dose of 15 Gy immediately prior to transfusion achieved corrected increments (CI) at 1 and 20 h after transfusion no different from those achieved by non-irradiated platelets. Storage for 5 days reduced the mean 1-hour CI to 5.7 compared with a mean of 12.3 achieved by platelets transfused after only 1-day storage (p = 0.008). Similarly, the frequency of a repeat transfusion being indicated within 24 h increased with increasing storage time (p = 0.005).