Related Experiment Video
Updated: Oct 4, 2026

In Vitro Thrombosis Test for Ventricular Assist Devices
Published on: March 21, 2025
Relationship between the heparin management test and the HemoTec activated clotting time in patients undergoing
S Tsimikas1, R Beyer, A Hassankhani
1Division of Cardiovascular Diseases, Department of Medicine, University of California San Diego, 9500 Gilman Drive, BSB 1080, La Jolla, CA 92093-0682, USA. stsimikas@ucsd.edu
Point-of-care whole blood coagulation tests are critical in the management of patients who undergo percutaneous coronary intervention. The Hemochron and HemoTec devices have been traditionally used to measure the activated clotting time (ACT) in the cardiac catheterization laboratory. The heparin management test (HMT) was recently introduced into clinical practice as an alternative method to current ACT measurements that uses a different sample volume, contact activators and detection system to measure whole blood coagulation. We compared the HMT to the HemoTec ACT in 68 prospectively enrolled patients (127 blood samples) undergoing percutaneous coronary intervention. Measurements were performed 10 minutes after the initial heparin bolus and thereafter at the discretion of the attending physician. The mean HMT was 41 seconds higher (approximately 15%) than the HemoTec ACT (HMT 304+/-59 vs. ACT 263+/-52, P< 0.0001), but there was a significant correlation between the methods (r=0.77, P<0.0001). However, there was increasing disagreement between the two methods as the level of anticoagulation increased. The relationship between HMT and ACT was similar in patients in whom glycoprotein IIb/IIIa inhibitors were used. The HMT, therefore, appears to be more sensitive to heparin anticoagulation that the HemoTec ACT and correlates well with it in the range required for percutaneous coronary intervention.
Point-of-care whole blood coagulation tests are critical in the management of patients who undergo percutaneous coronary intervention. The Hemochron and HemoTec devices have been traditionally used to measure the activated clotting time (ACT) in the cardiac catheterization laboratory. The heparin management test (HMT) was recently introduced into clinical practice as an alternative method to current ACT measurements that uses a different sample volume, contact activators and detection system to measure whole blood coagulation. We compared the HMT to the HemoTec ACT in 68 prospectively enrolled patients (127 blood samples) undergoing percutaneous coronary intervention. Measurements were performed 10 minutes after the initial heparin bolus and thereafter at the discretion of the attending physician. The mean HMT was 41 seconds higher (approximately 15%) than the HemoTec ACT (HMT 304+/-59 vs. ACT 263+/-52, P< 0.0001), but there was a significant correlation between the methods (r=0.77, P<0.0001). However, there was increasing disagreement between the two methods as the level of anticoagulation increased. The relationship between HMT and ACT was similar in patients in whom glycoprotein IIb/IIIa inhibitors were used. The HMT, therefore, appears to be more sensitive to heparin anticoagulation that the HemoTec ACT and correlates well with it in the range required for percutaneous coronary intervention.
Related Concept Videos
Anticoagulant Drugs: Low-Molecular-Weight Heparins
Venous Thrombosis III: Interprofessional Care
Pulmonary Embolism II: Diagnostic Studies and Interprofessional Care
Cardiac Catheterization I: Pre-Procedure Overview
Extrinsic and Intrinsic Pathways of Hemostasis
The Extrinsic Pathway
The extrinsic pathway of coagulation is typically initiated by tissue damage that exposes blood to tissue factor (TF), a protein released by the damaged tissue cells outside the blood vessels—this interaction with TF triggers biochemical reactions involving specific clotting factors. The key player here is Factor VII, which forms a...
Cardiac Catheterization IV: Nursing Management

