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Factor V Leiden Genotype

Published: July 27, 2026Updated: August 25, 2026

The Factor V Leiden genotype is a genetic variant that increases the risk of developing blood clots due to activated protein C resistance.

Quick summary

Factor V Leiden genotype predicts increased risk of thrombophilia.

Medically reviewed by WellAlly Editorial TeamLast reviewed August 25, 2026Editorial policy

Key facts at a glance

Units
genotype
Clinical utility
predictive
Result kind
qualitative
FDA-cleared
Roche Factor V Leiden PCR, Cepheid Factor V Leiden
interpretation: {"text":"The individual does not carry the Factor V Leiden mutation and has a typical risk of blood clots.","label":"Normal"}; {"text":"The presence of one or two copies of the Factor V Leiden mutation indicates an increased risk of thrombophilia.","label":"Heterozygous/Homozygous"}

Factor V Leiden is a genetic mutation that affects the blood clotting process by making the body resistant to activated protein C, a natural anticoagulant.

Individuals with this genotype have a higher risk of developing venous thromboembolism, especially in situations such as pregnancy, surgery, or prolonged immobility.

Testing for Factor V Leiden is important for identifying individuals who may benefit from preventive measures or altered treatment plans to reduce clotting risk.

Frequently asked questions

What is the significance of a positive Factor V Leiden test?
A positive test indicates an increased risk of developing blood clots, particularly in high-risk situations like surgery or pregnancy.
Should all individuals be tested for Factor V Leiden?
Testing is usually recommended for individuals with a personal or family history of unexplained blood clots.
  1. 1
    Factor V Leiden ThrombophiliaSource
  2. 2
    Factor V Leiden MutationSource

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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 25, 2026. · Read our editorial policy