[A kinetic micromethod of determining the activity of antithrombin III]

A method for measuring the blood plasma antithrombin III (AT III) activity is suggested, based on measurement of the rate of inactivation of added standard volume (0.05 ml) of plasma thrombin AT III. The thrombin residual activity in the mixture is detectable over the course of fibrinogen tests. Curves are plotted, reflecting the rate of inactivation of thrombin AT III in the tested and reference plasma samples; by modeling and comparing these curves the values of the examined sample AT III activity are obtained, with the effects of fibrinogen and fast antithrombins various levels eliminated.