THE RESULTS OF DIAGNOSTIC STUDIES FOR THROMBOPHILIA IN A LARGE GROUP OF PATIENTS WITH A PERSONAL OR FAMILY HISTORY OF THROMBOSIS

The range of tests used in the evaluation of thrombophilia has been al tered by the recent recognition of common genetic defects predisposing to thrombosis such as factor V-Leiden (FVR506Q), enzyme deficiencies causing hyperhomocysteinemia, and improvement in the sensitivity and u tilization of assays for antiphospholipid antibodies. In this study, t he outcomes of laboratory evaluation of 402 patients with thrombophili a were reviewed and correlated with clinical data. A predisposing fact or was present (positive diagnosis, group A) in 110 patients (27%), th e test results of 111 patients (28%) could not be definitively interpr eted (equivocal results, group B) and the test results of 181 (45%) we re normal (group C). The median age of the group A patients was 48 yea rs (range, 3.7-88 years), suggesting that evaluation of patients over the age of 50 is worthwhile. Of the 110 patients in group A, 84% had s ingle defects and 16% had combined defects. The most common defect was factor V-Leiden (44 patients). Equal numbers of patients presenting w ith arterial and venous thromboses were evaluated Patients with arteri al events were less likely to have a definable laboratory defect (33 o f 132 [25%]) than were chose with venous events (50 of 136 [37%]). Fac tor V-Leiden was the most frequent finding in patients with venous eve nts, and lupus anticoagulant or anticardiolipin antibodies were the mo st frequent findings in patients with arterial events. Positive diagno ses were made in patients on anticoagulants, indicating that this shou ld not preclude investigation. Our study confirms the need for thoroug h evaluation to assess thrombotic risk, and it reflects the impact of newly identified thrombophilic disorders on the expected outcome of la boratory evaluation for thrombophilia.