Thrombophilias and VTE

Thrombophilias are inherited or acquired conditions that increase an individual patient’s risk of VTE. Thrombophilias include disorders due to:

• deficiency of antithrombin or proteins C or S
• the presence of activated protein C resistance (eg factor V Leiden gene mutation)
• the prothrombin gene mutation (20210A)
• antiphospholipid antibodies—it is reasonable to test for antiphospholipid syndrome in all patients with an unprovoked VTE.

Do not perform hereditary thrombophilia testing in patients with a DVT or PE provoked by surgery or major trauma. Antithrombin and protein C and S deficiency can significantly increase the risk of recurrent VTETran, 2019; consider testing patients younger than 45 years with an unprovoked proximal DVT or PE.

The absolute risk of VTE for each of these conditions varies. Patients with an identified thrombophilia may require VTE prophylaxis, even for lower-risk situations; seek advice from a haematologist.