results of assays are expressed in casein units

SYNOPSIS Fibrinogen prepared by the method of Blomback and Blomback is most suitable with respect to sensitivity and stability for the estimation of urokinase by the fibrin plate technique. Adding plasminogen to a concentration of around 05 casein units/ml 0-2 g % clottable fibrinogen provides substrate conditions of optimal sensitivity and reproducibility. The fibrin plate is widely used in studies of the fibrinolytic,enzyme system in the measurement of plasminogen activator and plasmin. It was first described by Permin (1947) and later Astrup and Mullertz suggested optimal conditions for its use in the estimation of plasmin (Astrup and Mullertz, 1952). It is particularly useful for the estimation of the plasminogen activator present in urine, urokinas