An in vitro test of platelet viability.

The survival of transfused platelets is inversely related to the time of storage of platelets in vitro. The effects of storage on the ability of platelets to produce retraction of clots and on the morphologic alterations of platelets within the clots has been studied. The results suggest that clot retraction, using low concentrations of platelets, may be useful as an in vitro method for evaluating the viability of platelets.