A method using fibrin-fixed Blue Dextran for determining the plasmin and plasmin inhibitor activities in human plasma.

The fibrinolytic activity of plasmin was determined by incubating with fibrin-fixed Blue Dextran as a substrate, the Blue Dextran released being proportional to the plasmin activity. The applicability of this method for rapid and accurate evaluation of fibrinolytic activity was demonstrated by dose-response curves with purified plasmin, plasmin generated by urokinase in human plasma and euglobulin. The method can also be used to determined plasmin inhibitors in plasma.