Factor Five Leiden


Generally if you are being tested for FVL it is because you have a history of venous thrombosis or, you are being tested because of a strong family history. Basically there are two test to choose from. The first is called a rapid screening test or activated protein-c resistance test. This one is less expensive although it can not tell you if you are heterozygous or homozygous. The other test is the Factor Five Leiden, or DNA testing on the factor five gene. DNA testing would provide the status of your parents, so you would know if you are hetero vs. homozygous, for this reason the DNA testing is thought to be the best.

Factor Five Leiden can also increase your risk of inheriting or acquiring other blood coagulation disorders as well, such as antithrombin, protein C and S deficiencies and prothrombin. These would have to be tested for specifically and would not show up on the FV gene DNA testing.

All testing and treatment needs to be looked at based on a persons own history. This could be your personal or family history. Every persons risk for blood clotting, even those without FVL will increase with age, those 50 years old or more are generally at a greater risk over all. If you have FVL and have never had a thrombosis, but have a strong family history than your doctor may wish to wait until you approach 50 years old to begin any treatment for you or may decide that you need none at all. Each case needs to be looked at on a individual bases.

Testing for FVL should be considered if:

  • You are less than 50 years old when you have your first venous thrombosis
  • There is a strong family history for FVL and you have a venous thrombosis
  • If you have a venous thrombosis in a unusual place, such as cerebral or mesenteric
  • For recurrent venous thrombosis
  • If a women has a strong family history and wants to get pregnant, take birth control or hormone replacement therapy.