Clinical Opal - thrombophilia testing after a DVT

Clinical guidelines recommend against thrombophilia testing in Dimitri’s case.

In 2019, the Thrombosis and Haemostasis Society of Australia and New Zealand (THANZ) published new guidelines in the MJA on the diagnosis and management of venous thromboembolism (VTE), including recommendations for thrombophilia testing.1 They stated that patients with VTE provoked by surgery or major trauma should not be screened for hereditary thrombophilia.

There are a number of factors underpinning this recommendation. The presence of an inherited thrombophilia does not influence initial anticoagulant treatment. The predictive value of recurrent VTE conferred by the most common types of heritable thrombophilia (factor V Leiden and the prothrombin mutation) is limited. And the risk of recurrence associated with rare deficiencies of natural anticoagulants (antithrombin, protein C and protein S) is unclear.2

The guidelines state that it is reasonable to test in some specific scenarios:

• Young patients (< 45 years) with unprovoked proximal VTE should be tested for antithrombin and protein C and S deficiency if it influences treatment duration
• Patients with unprovoked proximal DVT and PE should be tested for antiphospholipid syndrome.

Additional important practice points include:

• Patients should be counselled regarding the potential significance of thrombophilia screening prior to testing
• Testing may be inaccurate in the presence of anticoagulation
• Patients with unprovoked proximal DVT and PE should be evaluated for malignancy by a thorough clinical assessment and age- and risk factor-appropriate screening.

For more information:

The rational use of pathology tests is a challenging area of general practice. Medcast have developed a free multimedia educational program, 'Testing, testing 1, 2, 3', to support GPs to use pathology tests more effectively, and reduce the harms of non-rational test ordering.

References

1. Tran HA, Gibbs H, Merriman E, Curnow JL, Young L, Bennett A, Tan CW, Chunilal SD, Ward CM, Baker R, Nandurkar H. New guidelines from the Thrombosis and Haemostasis Society of Australia and New Zealand for the diagnosis and management of venous thromboembolism. Med J Aust. 2019 Mar;210(5):227-235.

2. Ho WK, Hankey GJ, Eikelboom JW. Should adult patients be routinely tested for heritable thrombophilia after an episode of venous thromboembolism? Med J Aust. 2011 Aug 1;195(3):139-42.