24th July 2024

Overview of thrombophilia

Thrombophilia is a predisposition to clot formation and manifests clinically as VTE. These causes will be discussed:

• Factor V Leiden (FVL)
• Proteins C and S deficiency
• Antiphospholipid syndrome (APLS)

When the aetiology of a VTE is not known, it may be tempting to investigate whether there is an underlying thrombophilia. However, NICE only recommends screening for these conditions in certain circumstances:

• Consider testing for APLS in patients with unprovoked VTE where there are plans to stop anticoagulation
• Consider testing for hereditary thrombophilia in patients with unprovoked VTE who have a first-degree relative who has had a VTE and where there are plans to stop anticoagulation

These tests should not be offered routinely to family members of patients with a history of VTE. When thrombophilia testing is performed whilst patients are on anticoagulation the results will have to be interpreted with caution as they may be affected by the medication.