Fibrin powder turbidity measurement for rapid assessment of antiplasmins.

Fibrinolytic activity was determined from the rate of disappearance of turbidity in a suspension of heat-treated fibrin powder. Using this method for estimating residual fibrinolytic activity in mixtures of serum and plasmin, antiplasmin behaviors of specimens from patients with various clinical disorders were determined after long and short preincubation times. Slow-acting antiplasmins were found to be increased in a variety of conditions among these patients, while immediate acting antiplasmins were generally decreased, compared with those in specimens from a large pool of normal, healthy vounteers. Normal women taking oral contraceptives had consitently high levels of slow antiplasmins. Tests in vitro showed that the antifibrinolytic agents epsilon-aminocaproic acid, Trasylol and soybean trypsin inhibitor act only as fast antiplasmins.