Monitering of Human Plasma Prothrombin Activity with Ecarin

Objective: To develop a highly accurate and sensitive test for the determination of the activity of prothrombin in human plasma. Methods: Ecarin, a protease extracted from Echis carinatus venom, was used as the activator of prothrombin Ecarin clotting times (ECT) and chromogenic substrate method were used. Results: When the concentration of Ecarin was in the range of 1-8u/ml, ECT gradually prolonged with the dilution of the plasma. The correlation(γ) between ECT(lg) and plasma dilution(lg)1: 50, 1:100,1:200, 1:400, the correlation(7) between plasma dilution(lg) and absorption was more than -0. 943, P0.01; the correlation(γ) between the concentration of Ecarin(lg) and ECT(lg) was more than -0.957,P0.01. When the dilution of the plasma was (A) was -0. 957, P0. 01. Conclusion: Both the ECT and chromogenic substrate method were all sensitive to determine the activity of prothrombin in plasma.