COMPARISON OF A RECOMBINANT THROMBOPLASTIN WITH THROMBOTEST(TM) FOR ORAL ANTICOAGULANT CONTROL

Thrombotest(TM) results expressed in international normalized ratio (I NR) values, obtained in 108 patients on oral anticoagulant treatment, were compared with prothrombin time (PT) results with a recombinant th romboplastin. The former results were obtained on an Amelung coagulome ter, the latter on a photo-optical instrument. Using the Thrombotest m ethod, performed within 2 h after sampling as the reference method, a first group of 63 patients had an INR value between 2 and 4. This grou p was considered as adequately anticoagulated and served as a true pos itive population in further analysis. The remaining 45 patients (true- negative group) had an INR value below 2 or higher than 4 and could th us be considered as inadequately anticoagulated. Using these definitio ns, a sensitivity of 86% and a specificity of 96% could be calculated for the PT with the recombinant thromboplastin. All tests from patient s on oral anticoagulant treatment were also performed after 24 h stora ge of the blood or plasma samples at room temperature. When we compare d the reference Thrombotest results with those of the late Thrombotest and the late PT recombinant thromboplastin, sensitivities of 86 and 8 6% as well as specificities of 91 and 96% were found, respectively. In conclusion, PT with a recombinant thromboplastin on a photo-optical i nstrument, even after prolonged storage of the plasma samples at room temperature, can be considered as suitable for oral anticoagulation co ntrol.