Factor II and Factor V (Leiden) Genotyping

Factor V and II are blood clotting proteins. Variations in these proteins may increase the risk of dangerous cardiovascular events caused by venous thrombosis. In clinical studies, it has been shown that several genetic defects are associated with increased risk of venous thrombosis.[47] Physicians should consider testing any patient who has had a personal or family history of such events or those at high clinical risk of venous thrombosis, including patients taking medications that are potential contributors. Genetic variants tested are Factor II: c.*97G>A (g.20210G>A) and Factor V Leiden: c.1601G>A (c.1691G>A).

Indications for Factor II and Factor V Mutation Testing

Individuals with a personal or family history of first or recurrent venous thrombosis; who have had venous thrombosis at a young age (less than 50), venous thrombosis in unusual sites (hepatic, mesenteric, cerebral veins) or venous thrombosis in pregnancy; or with a combination of those who are also taking medications which individually increase the risk for venous thrombosis.