How should I approach the investigation for inherited thrombophilia in a patient with a history of venous thromboembolism?

Approach to investigating inherited thrombophilia in a patient with a history of venous thromboembolism (VTE):

• Consider thrombophilia testing only in patients with unprovoked VTE who have a first-degree relative with VTE, especially if there is a plan to stop anticoagulation treatment. This is because identifying hereditary thrombophilia in this group may influence the decision to continue long-term anticoagulation due to increased recurrence risk.
• Do not offer thrombophilia testing to patients who have had a provoked VTE (i.e., with recent major transient risk factors such as surgery, trauma, immobilisation, pregnancy, or hormonal therapy) as it does not change management.
• Do not offer thrombophilia testing to patients who are continuing anticoagulation treatment, since the results would not alter management.
• Be aware that thrombophilia tests can be affected by anticoagulant therapy, so specialist advice may be required regarding timing and interpretation of tests.
• Do not routinely offer thrombophilia testing to first-degree relatives of people with thrombophilia and VTE, as family history alone increases risk and thromboprophylaxis is recommended in high-risk situations regardless of test results.

This approach aligns with NICE recommendations to target testing where it may influence clinical decisions, avoiding unnecessary investigations that do not alter management or outcomes.

Summary: Test for inherited thrombophilia only in patients with unprovoked VTE who have a first-degree relative with VTE and when anticoagulation is planned to be stopped; avoid testing in provoked VTE, ongoing anticoagulation, or routine family screening NICE CKS,NICE NG158.