Factor V Leiden and Prothrombin genotyping

The Factor V Leiden and Prothrombin gene mutation test is a molecular test used to identify inherited thrombophilia, a condition that increases the risk of abnormal blood clot formation. Factor V Leiden is a specific mutation in the F5 gene that makes factor V resistant to inactivation by activated protein C (APC), leading to a higher risk of venous thromboembolism (VTE). The Prothrombin (F2) G20210A mutation is another common genetic variant that results in elevated prothrombin levels, contributing to an increased risk of clotting. These mutations are associated with deep vein thrombosis (DVT) and pulmonary embolism (PE).

The Factor V Leiden and Prothrombin gene mutation tests are recommended for individuals with a personal or family history of venous thromboembolism (VTE), including deep vein thrombosis (DVT) or pulmonary embolism (PE), particularly if events occurred unprovoked, at a young age (under 50), or in unusual sites (e.g., cerebral or mesenteric veins). However, genetic testing to predict a first episode of venous thrombosis is not recommended.

Testing is also indicated for those with recurrent pregnancy loss (especially in the second or third trimester), placental abruption, or other thrombotic pregnancy complications. Additionally, it may be advised prior to initiating estrogen-based therapies (e.g., oral contraceptives or hormone replacement therapy) or before major surgeries in high-risk patients. Asymptomatic family members of individuals with confirmed mutations might also be tested to assess inherited risk.

The laboratory is not UKAS accredited for FV Leiden and Prothrombin gene mutation tests.