OBJECTIVE: To compare the abilities of the heparin management test (HMT) and the activated coagulation time (ACT) to provide a measurement of heparin effect in patients undergoing cardiac or peripheral vascular surgery. These measurements of heparin effect were also compared with measurements of heparin concentrations tested by anti-Xa activity. A secondary objective was to compare the performance of the noncitrated HMT with that of the citrated HMT. DESIGN: A prospective study. SETTING: A single-center study conducted in a university hospital. PARTICIPANTS: After human investigation committee approval and informed consent were obtained, adult patients undergoing cardiac or peripheral vascular surgery were included in this study. INTERVENTIONS: In both surgical groups, blood was sampled for ACT, HMT, and anti-Xa activity. Each HMT was performed on both noncitrated and citrated samples. MEASUREMENTS AND MAIN RESULTS: As an indicator of heparin effect, the HMT had a strong correlation with the ACT (r = 0.899; p < 0.01). In addition, the HMT had a significantly stronger correlation with anti-Xa activity than the ACT (p < 0.01). The correlation obtained from the noncitrated samples was identical with that obtained from the citrated samples (r = 0.819; p < 0.001 for both groups). CONCLUSION: The ability of the HMT and the ACT to measure heparin effect was similar. The HMT performed better than the ACT when using anti-Xa activity as a measure of heparin concentration. Noncitrated HMT results were similar to citrated HMT results, thus supporting the use of fresh whole blood for testing purposes.
OBJECTIVE: To compare the abilities of the heparin management test (HMT) and the activated coagulation time (ACT) to provide a measurement of heparin effect in patients undergoing cardiac or peripheral vascular surgery. These measurements of heparin effect were also compared with measurements of heparin concentrations tested by anti-Xa activity. A secondary objective was to compare the performance of the noncitrated HMT with that of the citrated HMT. DESIGN: A prospective study. SETTING: A single-center study conducted in a university hospital. PARTICIPANTS: After human investigation committee approval and informed consent were obtained, adult patients undergoing cardiac or peripheral vascular surgery were included in this study. INTERVENTIONS: In both surgical groups, blood was sampled for ACT, HMT, and anti-Xa activity. Each HMT was performed on both noncitrated and citrated samples. MEASUREMENTS AND MAIN RESULTS: As an indicator of heparin effect, the HMT had a strong correlation with the ACT (r = 0.899; p < 0.01). In addition, the HMT had a significantly stronger correlation with anti-Xa activity than the ACT (p < 0.01). The correlation obtained from the noncitrated samples was identical with that obtained from the citrated samples (r = 0.819; p < 0.001 for both groups). CONCLUSION: The ability of the HMT and the ACT to measure heparin effect was similar. The HMT performed better than the ACT when using anti-Xa activity as a measure of heparin concentration. Noncitrated HMT results were similar to citrated HMT results, thus supporting the use of fresh whole blood for testing purposes.