HUSSEIN, K.A. and Al-HASSAN, J.M. A Simple Spectrophotometric Method for the Determination of Thrombin Activity. Tohoku J. exp. Med., 1987, 153 (1), 1-4 - The activity of thrombin in commercial preparations was measured by an easy, precise spectrophotometric method that allows determination of thrombin activity in dilute solutions more accurately than other methods hitherto used. The method can also be used to compare fibrinogen content in plasma samples.