Skip to main content

Use of a functional assay to diagnose protein S deficiency; inappropriate testing yields equivocal results

Buy Article:

$51.00 plus tax (Refund Policy)


Inherited deficiency of protein S (PS) is a rare but accepted risk factor for venous thromboembolism. There is accumulating evidence that inherited PS deficiency may be associated with a variety of adverse obstetric events. Acquired PS deficiency may be caused by a variety of clinical states including normal pregnancy. We conducted a retrospective audit of the results of screening for PS deficiency through our reference laboratory. The majority of patients in this audit with significantly reduced (<50%) free functional PS levels had a major confounding factor likely to cause acquired PS deficiency, most frequently pregnancy. Recommendations for PS testing for the diagnosis of hereditary PS deficiency include deferring testing until at least 40 days post‐partum. It appears that these recommendations are not being adhered to leading to difficulty in the interpretation of results.

Keywords: blood coagulation tests; pregnancy; protein S deficiency; thrombophilia; venous thromboembolism

Document Type: Research Article


Affiliations: Northern Blood Research Centre, University of Sydney, Royal North Shore Hospital, Sydney, New South Wales, Australia

Publication date: 2007-06-01

  • Access Key
  • Free content
  • Partial Free content
  • New content
  • Open access content
  • Partial Open access content
  • Subscribed content
  • Partial Subscribed content
  • Free trial content
Cookie Policy
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more