Medical knowledge, Patient Education
Factor V Leiden Test
Why am I having this test?
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You experienced an unexplained clotting event.
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You have a family history of blood clots.
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You had a blood clot before the age of 30.
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You had a blood clot during pregnancy or while taking birth control pills.
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You had a blood clot in an unusual vein location.
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You had a blood clot in an artery.
What is being tested?
This test checks for the factor V Leiden genetic mutation through DNA analysis of the factor V gene. Factor V is an important protein involved in normal blood clotting. The abnormal form of factor V (factor V Leiden) can increase the risk of blood clotting.
What kind of sample is taken?
A blood sample is required for this test. It is usually collected by inserting a needle into a blood vessel.
Tell a health care provider about:
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All medicines you are taking, including vitamins, herbs, eye drops, creams, and over-the-counter medicines.
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Any medical conditions you have.
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Any bleeding problems you have.
How are the results reported?
Your test results will be reported as either positive or negative for the factor V Leiden genetic mutation. If the results are positive, more specific information about the genetic mutation may also be included.
What do the results mean?
A negative test result means that no genetic defect was found.
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Heterozygous. This means that only one of the two factor V genes has a mutation. A person with this result has a slightly increased risk for clotting.
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Homozygous. This means that both of the factor V genes have a mutation. A person with this result has a much higher risk of clotting.
Talk with your health care provider about what your results mean. In some cases, your health care provider may do more testing to confirm the results.
Questions to ask your health care provider
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When will my results be ready?
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How will I get my results?
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What are my treatment options?
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What other tests do I need?
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What are my next steps?
Summary
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The factor V Leiden test is done to determine whether you have an inherited gene mutation that increases your risk of developing blood clots.
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A positive test result indicates the presence of the factor V Leiden genetic mutation.
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Talk with your health care provider about what your results may mean.
This information is not intended to replace advice given to you by your health care provider. Make sure you discuss any questions you have with your health care provider.
