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.
This test is not currently accredited
Record last updated
August 18, 2025
Sample Container
4ml EDTA Vacutainers (Lavender top)
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Test Results
Yes, we have a Pathology User Guide
Yes. Please email your request to Imperial.nwlpcustomerservice@nhs.net
Results are communicated to clinical staff and are normally not communicated direct to patients either on telephone requests or in written report. If you need to contact us please click here to view the contact details page
Please contact the Customer Service Team Monday to Friday from 8:30am – 6:00pm on 0203 313 5353. Alternatively, see the Pathology User Guide for how to contact the relevant department. If advice is not urgent you can also email your query to Imperial.nwlpcustomerservice@nhs.net
Additional tests may be added by discussion with the relevant laboratory. The time limit for adding additional tests to a sample already received in the laboratory will depend on the type of sample and the department it was sent to.
Information on the repertoire of tests performed by pathology, including reference ranges, turnaround times and specimen requirements, can be found in the test directory.
Phlebotomy services are not managed by NWLP. For further information please see:
Imperial College Healthcare Trust Phlebotomy services
Chelsea and Westminster Hospital NHS Foundation Trust Phlebotomy services
NWLP operates UKAS accredited medical laboratories as per the references below. The current scope of accreditation for all NWLP’s laboratories can be found on the UKAS website.
See the following UKAS ref numbers:
- Clinical Biochemistry Ref: 8673
- Haematology and Blood Transfusion Ref: 8674
- Infection & Immunity Sciences (Including Immunology, Virology, Microbiology and Histocompatibility and Immunogenetics ) Ref: 8659
- Cellular Pathology (Including Histopathology, Cytology and Molecular Pathology) Ref: 9615
If you require copies of our certificate of accreditation and associated documentation please contact Imperial.nwlpcustomerservice@nhs.net.
UKAS requires the laboratories to be accredited for a particular repertoire/scope (ISO15189), any changes or additions to repertoire require assessment by UKAS (extension to scope).
The BD Hospital Tube Guide, BD GP Tube Guide and BD Paediatric Tube Guide provide visual references to the correct tube types and collection instructions.
Home testing
INSTRUCTION SHEET FOR BLOOD SAMPLE COLLECTION
We also have two instruction videos available (one with subtitles and one without) – please click on the links to view the videos on Google.
Our accreditations
Upholding excellence in diagnostic standards
Our laboratories are accredited by the UK Accreditation Service (UKAS) against the international standard ISO15189:2022. UKAS is the accreditation body for the UK that assesses medical laboratories.
Find out more about our accreditations on the UKAS website.
UKAS website