Diagnosis

A blood test can confirm the diagnosis of factor V Leiden. The test may be a blood-clotting study or a genetic test. Your healthcare professional may order the test if you've had one or more blood clots or if you have a strong family history of blood clots.

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Treatment

Healthcare professionals most often prescribe blood-thinning medicines to treat people who get blood clots. People who have the factor V Leiden gene change but who have not had blood clots don't need this medicine.

If you have the factor V Leiden gene change and you need to have any type of surgery, your healthcare professional might suggest that you take extra care to prevent blood clots. This may include:

  • Taking blood thinners for a short time.
  • Using leg wraps that inflate and deflate to keep blood moving in your legs.
  • Wearing stockings that put pressure on your legs, called compression stockings.
  • Going for walks soon after surgery.

For people who are pregnant and have the factor V Leiden gene, a healthcare professional may suggest taking blood thinners during pregnancy and for a time after giving birth.

Lifestyle and home remedies

Some ways to help lower your risk of blood clots include:

  • Keep your legs moving. When you move your legs, the muscles tighten. This tightening, called contracting, helps blood move through your body.

    On a long plane trip, raise your toes up and down, and rotate your ankles every hour or so. Drink extra water to keep from losing fluids. Don't drink alcohol. On a car trip, take breaks every so often and walk around.

  • Wear compression stockings.These stockings most often come up to the knees. They help keep blood moving by pressing on your legs. Ask your healthcare professional if they might help you.
  • Be careful about taking the hormone estrogen. Birth control pills or estrogen replacement therapy can raise the risk of blood clots. So talk with your healthcare professional before taking medicines with estrogen if you have factor V Leiden.

Prevent bleeding

If you take blood-thinning medicine for factor V Leiden, these steps might help you prevent injury and keep you from bleeding too much:

  • Don't play contact sports or do other activities that could result in injury. Do regular, gentle exercise for good health. Exercises might include walking or swimming.
  • Use a soft toothbrush and waxed floss.
  • To keep from cutting yourself while shaving, use an electric razor.
  • Be careful with household tasks that involve knives, scissors and other sharp tools.

Preparing for your appointment

Your healthcare professional may send you to a specialist in genetic conditions, called a geneticist, or a specialist in blood conditions, called a hematologist. They can test to see whether changed genes are the cause of your blood clots and whether you have factor V Leiden.

Here's some information to help you get ready for your appointment.

Make a list of:

  • All your symptoms, and when they began.
  • Your health history, including your history of blood clots. Include any family history of blood clots or family members that have factor V Leiden.
  • All medicines, vitamins and supplements you take, including dosages.
  • Questions to ask your healthcare professional.

For factor V Leiden, some questions to ask your healthcare professional include:

  • What tests do I need?
  • Do I need to see a specialist?
  • Do I need treatment for factor V Leiden? Does that include medicine to prevent blood clots?
  • What types of side effects can I expect from the medicine?
  • Do I need to limit my activity?
  • Do my children need to be tested?
  • Do you have brochures or other printed material that I can have? What websites do you suggest?

If your healthcare professional suggests genetic testing, some questions to ask the genetic specialist may include:

  • How likely is this test to be right?
  • What are the risks of the test?
  • What will a positive or negative result tell me?
  • Can the results of the test affect my health insurance?
  • What would a test result that isn't certain mean?
  • What are my treatment options if I have factor V Leiden?
  • Should my children be tested?
  • How long will it take to get the test results?
May 12, 2026

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  2. Middeldorp S. Factor V Leiden and activated protein C resistance. https://www.uptodate.com/contents/search. Accessed Feb. 17, 2025.
  3. AskMayoExpert. Factor V Leiden. Mayo Clinic; 2023.
  4. Venous thromboembolism. National Heart, Lung, and Blood Institute. https://www.nhlbi.nih.gov/health/venous-thromboembolism. Accessed Feb. 17, 2025.
  5. Middeldorp S, et al. American Society of Hematology 2023 guidelines for management of venous thromboembolism: Thrombophilia testing. Blood Advances. 2023; doi:10.1182/bloodadvances.2023010177.
  6. Blood thinner pills: Your guide to using them safely. Agency for Healthcare Research and Quality. https://www.ahrq.gov/patients-consumers/diagnosis-treatment/treatments/btpills/btpills.html. Accessed Feb. 18, 2025.

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