Laboratory test utilization in the diagnosis of hypercoagulability.

OBJECTIVE To determine the appropriateness and utility of laboratory tests ordered by physicians for evaluation of hypercoagulability. DESIGN Retrospective review of patient charts was performed to collect information on patient demographics, clinical history, coagulation testing, interpretation of results, and clinical decisions. SETTING/SAMPLE Subjects included all patients from a 400-bed acute care hospital who had a laboratory workup for hypercoagulability within the most recent 12-month period. Thirty-four patients whose medical records were available and whose clinical history included thrombosis were included in the study. MAIN OUTCOMES/CONCLUSIONS: Eighty-two percent of the patients had a familial and/or acquired risk factor for thrombosis. Over 40% had abnormal coagulation test results. Up to one-third of the tests were ordered and performed while the patient was on anticoagulant therapy. In over 50% of the cases with abnormal results, the physicians' notes did not mention the abnormality or the abnormal result was considered normal. These results indicate that although physicians are selecting the appropriate patients for laboratory test workup for hypercoagulability, the testing is being performed at an inappropriate time after the thrombotic event and the results of laboratory tests are often not utilized in patient diagnosis and management.