Related Experiment Video
Updated: Oct 11, 2026

Rapid Point-of-Care Assay of Enoxaparin Anticoagulant Efficacy in Whole Blood
Published on: October 12, 2012
The effect of operation and subcutaneous heparin on plasma levels of antithrombin-III
Plasma antithrombin III (AT-III) levels were measured in 61 patients undergoing general surgery. The patients were randomly allocated to a test or a control group. The test group received 5000iu of subcutaneous heparin two hours before operation and then twelve hourly for seven days. The control group received subcutaneous saline. Plasma levels of AT-III and of heparin were estimated before operation, at two, four and six hours after heparin injection on the day of operation and thereafter before the morning injection on the first, third and sixth postoperative days. Antithrombin III decreased progressively during and after operation in both groups. The decrease was greater in the test group at six hours after the first injection. These findings support the hypothesis that AT-III is consumed during coagulation and its utilization is increased in the presence of heparin.
Plasma antithrombin III (AT-III) levels were measured in 61 patients undergoing general surgery. The patients were randomly allocated to a test or a control group. The test group received 5000iu of subcutaneous heparin two hours before operation and then twelve hourly for seven days. The control group received subcutaneous saline. Plasma levels of AT-III and of heparin were estimated before operation, at two, four and six hours after heparin injection on the day of operation and thereafter before the morning injection on the first, third and sixth postoperative days. Antithrombin III decreased progressively during and after operation in both groups. The decrease was greater in the test group at six hours after the first injection. These findings support the hypothesis that AT-III is consumed during coagulation and its utilization is increased in the presence of heparin.
Related Concept Videos
Therapeutic Index
Anticoagulant Drugs: Low-Molecular-Weight Heparins
Anticoagulant Drugs: Vitamin K Antagonists and Direct Oral Anticoagulants
Warfarin, a prominent vitamin K antagonist family member, exerts its effect by inhibiting the enzyme VKORC1 (vitamin K epoxide reductase complex 1). By hindering this enzyme, warfarin...
Venous Thrombosis I: Introduction
Venous Thrombosis II: Clinical Manifestations and Diagnostic Studies
Venous Thrombosis III: Interprofessional Care

