Screening test for thrombophilic patients: which tests, for which patient, by whom, when, and why?

In the past two decades, several mechanisms leading to thrombophilia have been elucidated, and corresponding laboratory tests developed. At a time of financial constraints, it is crucial to distinguish between the tests of proven value (which can modify the therapeutic attitude toward the patient and/or his family) from those of unproven value. We have listed in the first category determination or measurement of factor V Leiden, factor II G20210A, antithrombin, protein C, protein S, as well as antiphospholipid antibodies and hyperhomocysteinemia. A combined clinical and laboratory approach taking into account the history of the patient and his family, the prevalence of the defects, and also the accuracy of the tests should allow tailoring a laboratory testing program to each individual patient. It is essential to keep in mind that the more difficult task is not to perform the tests, but to consider who will benefit from testing both for prevention and therapy of venous thromboembolism. The present review provides answers to some of these issues. These answers should, however, be considered as provisional because new findings and study results will certainly modify them in the future.