Summary
The theroretical basis for the use of a one-stage lysis time method for determination of urokinase is outlined. The calculations are based on experiments with purified plasminogen, fibrinogen, and thrombin preparations.
The following correlation between the lysis time and the urokinase, plasminogen, and fibrinogen concentrations was found : 
This correlation is valid onyl for a certain range of plasminogen and urokinase concentrations. This validity has been verified experimentally.
A method has been proposed for determination of urokinase in which the curve of the standard graph always is rectilinear and has the slope –0.5. The method is very sensitive and its accuracy is great.
