Another message from colleague and friend Kelly Townsend, Tricore Reference Laboratories, Albuquerque. Hi George, at one of our large teaching hospitals, we are working with the Internal Medicine department to establish “best practices” for ordering thrombophilia testing on inpatients. Has anyone out there successfully implemented guidelines they are willing to share? Any recent references would also be greatly appreciated. Thanks!
Hello again, Kelly and thank you for your question. Thrombophilia testing is generally discouraged for inpatients, as many assays are affected by inflammation, drugs (especially anticoagulants, of course) and current or recent thrombotic events. The assays you can rely on during acute events are the molecular tests for factor V Leiden and prothrombin 20210 mutations and immunoassays for anti-cardiolipin and beta-2-glycoprotein 1 antibodies. Antithrombin and protein C and S activity and antigen assays are only reliable when the patient is asymptomatic and drug-free, same for the activated protein C resistance ratio, and in many cases, clot-based lupus anticoagulant testing. These are typically made available only to outpatients. The test for plasminogen activator inhibitor-1 (PAI-1), plasma homocysteine testing, and molecular tests for the MTHFR polymorphisms seem to offer little towards prognosis or treatment.
If you will pardon some self-promotion, your internists may wish to consult Marques MB, Fritsma GA, Quick Guide to Coagulation Testing, 2nd Edition, 2009, AACC Press, or Chapter 42 in Thrombosis Risk Testing in Rodak BF, Fritsma GA, Keohane EM. Hematology, Cllinical Principles and Applications, 2012, Elsevier. One well-cited article that discourages widespread thrombophilia testing is Middledorp S. J Thromb Thrombolysis. 2011; 31: 275–81, which is attached below. I’ll be interested in learning what other institutions are doing about thrombophilia testing.
Mar 29 2014
Comments (1)
Thrombophilia
Dear Kelly,
Inpatient testing for thrombophilia appears to b
Dear Kelly,
Inpatient testing for thrombophilia appears to be a waste of time. In an audit of 500 consecutive patients who had thrombophilia testing requested in our laboratory, the majority were outpatients but in a subset of 73 inpatient requests for thrombophilia, 45% were at an acute stage of thrombosis, 29% were ordered before thrombosis had been proven and the remaining 26% were not being investigated because of thrombosis (according to the patients’ records). The guidelines from the British Committee for Standards in Haematology (BCSH) and the British Society for Haematology) published in BJH (2010) 149, 2009 are very sensible in my opinion but we have had very little success in implementing them.