Thrombin-induced serotonin release as an in vitro indicator of the functional integrity of stored platelets

Measurements of endogenous serotonin and the thrombin-induced serotonin release reaction in platelet concentrates were compared with other methods of quality control: particle counting and pH and gas analyses. A discrepancy between the serotonin release reaction and the other data was observed after seven days of storage. The decline in the release reaction was not predictable from pH measurements or the number of platelets or leukocytes in the concentrate. There was a significant positive correlation between endogenous serotonin content and the thrombin-induced serotonin secretion after seven days of storage. We conclude that the current methods for routine control of platelet concentrates may not ensure the quality of the product after it has been stored for seven days. The thrombin-induced serotonin release may provide a valuable addition to the battery of tests available.