Hypocoagulability of Certain Irradiated Plasmas

Since it has become obvious that certain batches of pooled human plasma transmit the virus causing homologous serum jaundice, methods have been developed to insure the sterilization of the plasma. Of these methods, the one coming into widest use is the exposure of plasma to ultraviolet radiation. A large number of transfusions of such material has been given, apparently without causing any untoward effects. It has been stated that plasma subjected to ultraviolet irradiation is unchanged in chemical and electrophoretic behavior. 1 Recently we have found profound alterations of the clotting mechanism in certain samples of irradiated plasma which may prove to be of academic and clinical interest. In these experiments the following substances were used: (1) irradiated liquid normal human plasma (M. R. plasma) 2 ; (2) lyophilized irradiated normal human plasma (S. D. lyophilized plasma) 3 ; (3) irradiated normal human plasma, not lyophilized (S. D. plasma) 4 ; (4) citrated