An improved method for evaluation of blood coagulation in heparinized blood

A simple method designed to allow coagulation studies in heparinized blood was evaluated. Citrated plasma containing heparin was incubated with an anion-exchange resin commercially available in tablet form (Heparsorb). After centrifugation of the mixture, coagulation studies were carried out on the supernatant plasma. One heparin neutralizer (HN) tablet was capable of removing as much as 43 units of heparin from 1 ml plasma within 10 min of incubation. When normal plasma was exposed to the heparin neutralizer, little or no change in the activities of clotting factors XII, XI, VIII, VII, X, V, and II was observed. However, the resin caused a substantial (44%) loss of factor IX-activity from normal plasma. This loss of factor IX-activity was not observed with plasma from patients receiving coumadin therapy. The results of coagulation tests (aPTT, PT, TT) and determination of fibrinogen/fibrin degradation products performed with HN-treated plasmas from nine patients receiving heparin therapy for thromboembolic disease and seven patients undergoing cardiopulmonary bypass operations were virtually identical to those obtained for the same persons before heparin was administered. The method, which is suitable for the routine clinical laboratory, may be useful in the hemostatic evaluation of critically ill patients who experience bleeding complications while receiving heparin therapy, in the laboratory control of coumadin therapy during the heparin-coumadin overlap period, and in the rapid identification of heparin contamination of blood specimens as a cause of an unexplained aPTT prolongation.