Experience with a Thrombin Clotting Time Assay for Measuring Heparin Activity

Abstract

A method for measuring heparin activity, the thrombin clotting time (TCT) has been employed over the past 10 years to monitor heparin therapy. The procedure as it has evolved requires thrombin and calcium, readily available reagents, which are stable under the conditions described. In comparison wiui other assays of heparin activity, the TCT provides greater specificity and convenience and permits quantitative determinations of heparin activity in terms of heparin antithrombin units.