The factor V G1691A (factor V Leiden, FVL) and factor II G20210A gain-of-function mutations are the most frequent forms of inherited thrombophilia [1,2]. However, considering their prevalence in the healthy Caucasian population (3–10% depending on the region), the increase in thromboembolic risk is merely 3–5 times that of non-carriers and the large majority of carriers will not suffer any thromboembolic event [1,3]. Therefore, screening for the presence of FVL and G20210A is controversial, particularly in patients without a strong personal or familial history of thrombosis and those in whom the results would not have therapeutic implications.
