Deep venous thrombosis in surgical patients: possible laboratory predictors

We tested 18 surgical patients before and after operation in an effort to determine whether or not laboratory tests could be used as predictors of deep venous thrombosis. During the period of study, none of the patients tested had deep venous thrombosis. Coagulation tests showed no significant changes, but all tests used to measure platelet numbers and functions yielded different preoperative and postoperative values. Testing of spontaneous platelet aggregation and platelet aggregate ratios suggested that some patients had hyperactive platelets preoperatively. Some postoperative changes suggested selective use of hyperactive platelets, but we could not determine the usefulness of such tests as predictors of thrombosis.