Thrombin clotting time and fibrinogen concentration in patients treated with coumadin

Thrombin clotting times and fibrinogen levels were measured in plasma from patients on chronic coumadin therapy who had prolonged prothrombin times. Thrombin clotting times were usually prolonged. Fibrinogen concentrations were generally elevated, but some were normal or even low. There was no evidence for disseminated intravascular coagulation. Comparison of thrombin clotting times and fibrinogen levels in normal plasma demonstrates that as fibrinogen concentration increases the thrombin clotting time lengthens. A similar correlation was found in many of the patients tested.