What are the recommended initial tests for a patient suspected of having thrombophilia?

For a patient suspected of having thrombophilia, initial investigations for thrombophilia itself are typically considered after a venous thromboembolism (VTE) event, particularly if it was unprovoked ¹,³. Thrombophilia testing involves investigating for acquired or inherited predispositions to venous thrombosis, including deficiencies in natural anticoagulants like antithrombin, protein C, and protein S, or the presence of antiphospholipid antibodies ¹.

• Consider testing for antiphospholipid antibodies in people who have had an unprovoked deep vein thrombosis (DVT) or pulmonary embolism (PE) if there is a plan to stop anticoagulation treatment ¹,³.
• Consider testing for hereditary thrombophilia in people who have had an unprovoked DVT or PE and who have a first-degree relative with DVT or PE, especially if there is a plan to stop anticoagulation treatment ¹,³.

It is important to note that these tests can be affected by anticoagulants, and specialist advice may be required ¹,³.

Thrombophilia testing is generally not offered in the following circumstances:

• To people who have had a provoked DVT or PE ¹,³.
• To people who are continuing anticoagulation treatment, as it will not alter management ¹,³.
• Routinely to first-degree relatives of people with a history of DVT or PE and thrombophilia ¹,³.

As part of the initial management for suspected DVT or PE (which may precede consideration of thrombophilia testing), baseline blood tests are performed. These include a full blood count, renal and hepatic function, prothrombin time (PT), and activated partial thromboplastin time (APTT) ¹,²,³. These baseline tests are crucial for managing anticoagulation and reviewing medical history, but they are not specific diagnostic tests for thrombophilia itself ¹,²,³.