The 67 patients with VTE on TT also were more likely than the 76 VTE no-TT controls to have the lupus anticoagulant, 9/64 (14%) versus 2/76, 3%, P = .023.4 When screening men4 for thrombophilia before starting TT, we suggest that minimal tests include the factor V Leiden mutation and the lupus anticoagulant, while more extensive tests would also include PCR for the G20210A prothrombin gene mutation, factors VIII and XI, and homocysteine. Here, F5 is linked to Rare hereditary thrombophilia.