A comparison of five devices for the bedside monitoring of heparin therapy.

Five instruments were tested for their capacity to monitor heparin therapy on whole blood at the bedside. The instruments were 512 Coagulation Monitor (Ciba-Corning), Thrombotrack (Nycomed), Automated Coagulation Timer (Hemotec), Hemochron-ACT and Hemochron-APTT (International Technidyne Corporation). Fifty subjects with various levels of heparinisation were tested on each instrument and were also assayed for antithrombin III, fibrinogen, haematocrit, platelet count and plasma heparin level. The results were compared with a reference APTT performed on the Automated Coagulation Laboratory 300R (Instrumentation Laboratories). The Hemochron-ACT correlated least well. The Hemotec and Thrombotrack were unsuitable in a clinical setting because of pipetting requirements, although the Thrombotrack did correlate well with the reference parameters. The 512 Coagulation Monitor was the simplest to use, but its maximum response corresponded to the midpoint of the reference APTT therapeutic range. The Hemochron-APTT was simple to use, had an adequate response range and correlated well with reference parameters.