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.