A heparin test as a predictor of postoperative deep vein thrombosis

A heparin test was developed and tested to determine if it could predict which patients were likely to develop postoperative deep vein thrombosis (DVT). The test was based on the observation that approximately one-third of normal subjects have a reduced anticoagulation response to heparin. Fifty-four adult patients undergoing abdominal operations, and who were not receiving DVT prophylaxis, were pre-operatively given 20 u heparin/kg intravenously and the thrombin clotting time was determined 30 min later (TCT 30). Forty-two had a normal response of a TCT 30 greater than 120 s, the remainder having a positive test of TCT 30 less than 120 s. The heparin test accurately predicted four of the seven patients who developed postoperative DVT as determined by the 125I-fibrinogen test, and correctly identified 39 of the 47 who did not develop DVT (P less than 0.05). No patient developed clinical DVT. This simple test could be of practical value in clinical surgery in predicting which patients are at risk of postoperative DVT and require prophylaxis.