Deficiency of plasma prothrombin conversion accelerators in the postoperative state with a description of a simple method of assay.

By RICHARD WARREN, M.D. AND JOHN S. BELKO, M.S. A PRACTICAL CLINICAL METHOD for determining the activity in plasma of the accelerators of prothrombin conversion has not been so rapidly forthcoming as have been descriptions of their properties and reactions. Those methods which have been described have employed two general principles. The first. of these is the ability of the unknow’n plasma to restore the total prothrombin activity of a mixture from which prothrombin accelerators have been totally or partially removed ; the second the comparison of the total prothrombin activity of a given unknown done by a standard method with that done similarly 1)Ut in the presence of an excess of prothrombin conversion accelerators. In the following report “prothrombin conversion accelerator” is used as an