Oral Presentation Australian Institute of Medical Scientists National Scientific Meeting 2013

The Futility of Testing for Thrombophilia (#20)

Emmanuel Favaloro 1
  1. ICPMR, Pathology West, Westmead, NSW, Australia

Thrombophilia can be defined as an increased tendency towards thrombosis. Given a thrombotic event in any given individual, the patient and treating physician may wish to know ‘why this has happened’. This has lead to an explosion in pathology test requests for thrombophilia investigations. Markers associated with thrombophilia include: 1. congenital disorders such as Factor V Leiden; prothrombin G20210A; antithrombin, protein C, or protein S deficiencies; 2. Acquired disorders, such as antiphopholipid syndrome characterised by the presence of lupus anticoagulant (LA). Although performance of such tests may be useful when investigating thrombophilia in select individuals, testing is not warranted in most cases, wastage of valuable health resources, and provides a high risk of false positive diagnoses. As examples: (a) testing patients placed on anticoagulant therapy (low protein C or S levels leading to falsely identifying ‘deficiencies’); notably, audits of practice reveal that at least one third of test requests arise in patients while on anticoagulant therapy. (b) although APS is associated with pregnancy morbidity and mortality, another ( six month) audit of practice revealed the absence of positivity for LA for all cases referred from the obstetrics team , suggesting poor patient selection. (c) another audit revealed that test requests for Factor V Leiden in men simply followed the pattern of increasing thrombosis occurrence with age, rather than age-appropriate test requests . In total, there is futility rather than utility in current practice associated with thrombophilia testing, and inappropriate thrombophilia testing according to inappropriate clinical requests has great potential for patient harm, due to false diagnosis of deficiencies, and potential for inappropriate clinical therapies.