Studies on Preserved Human Blood. V. Decrease in Prothrombin Titer During Storage.∗

Summary The rate of disintegration of the plasma prothrombin in preserved blood stored aseptically at 5° was studied by the quantitative prothrombin method of Warner, Brinkhous and Smith. The prothrombin values were found to decrease very gradually, reaching the 50% level at the end of about 3 weeks. No difference in the rate of disintegration was found between blood stored in sodium citrate and that stored in a citrate-dextrose mixture.