Appropriateness of Thrombophilia Testing in Tertiary Care Centers in Edmonton

Abstract

INTRODUCTIONThrombophilia is associated with an increased risk of venous thromboembolism (VTE). Despite this link, determining the presence or absence of such conditions has no role in VTE management including determining the choice or duration of anticoagulant therapy. Testing can be potentially harmful when results are misinterpreted or impact patient anxiety and insurance eligibility.METHODSWe performed a retrospective chart review of adult patients presenting to the emergency department (ED) or were admitted to the University of Alberta Hospital (UAH), Royal Alexandra Hospital (RAH) and Grey Nuns Hospital (GNH) and underwent any number of thrombophilia tests (including factor V Leiden [FVL], prothrombin gene mutation [PT20210], protein C [PC], protein S [PS], antithrombin [AT] and antiphospholipid antibody testing). To assess for appropriateness of testing, categories of data were collected including presence of other strong risk factors obviating the need to look for other causes, indicators for higher yield (age of patient, presence of family history of VTE, idiopathic nature of VTE), presence of factors that confound testing (such as therapeutic anticoagulation) and relevant follow up (appropriate repeat testing when necessary). We also collected basic patient demographics, VTE details and ordering physician/service details to evaluate under what circumstances testing may be ordered more frequently.RESULTS134 charts of patients tested for thrombophilia were reviewed between 2007-2013 at UAH and RAH Hospitals. A total of 965 thrombophilia tests were done (see analysis table). 13.4% of the testing was ordered by hematologists, 23.1% by neurologists, 52.2% by other internists. Overall, all patients had tests performed inappropriately, lacked appropriate follow up or had uninterpretable results and none had documented counseling prior to thrombophilia testing.CONCLUSIONSThrombophilia testing is frequently ordered inappropriately and not adequately followed up. Strategies to educate physicians on indications and limitations of testing are warranted. These strategies can help decrease over/under/misinterpretation of thrombophilia testing as well as result in significant savings to the health care system if testing can be reduced.Table 1DemographicsSample SizeMalesFemalesTotal74 (55.22%)60 (44.78%)134 (100%)Age at time of testing (Yrs)Range19-88Average48.7Patients' Test ResultsTestTimes PerformedAbnormal ResultsAPCR134 (100%)32 (23.8%)FVL genetic test58 (43%)21 (39%)PT20210105 (77%)4 (3.8%)Protein C100 (74.1%)8 (8%)Protein S99 (73.3%)16 (16.2%)AT levels99 (73.3%)19 (19.2%)Anticardiolipin Ab117 (86.7%)4 (3.4%)Lupus Anticoagulant109 (81.3%)10 (10.2%)Provoking FactorsPatients with One or More Provoking FactorsMajor107.4%Moderate7456%Minor2921.8%No Provoking Factors4936.8%Family History of VTE128.9%Protein C and Protein S TestingDone During Acute VTE6464%Patient was on Warfarin2525%Number of Abnormal Test Results2416%Number of Repeated Abnormal Tests00%AT TestingTotal Tests Performed9973.3%Done During Acute VTE6263%Patient was on Therap. Heparin or LMWH6262.6%Number of Abnormal Test Results1919.2%Abnormal Tests Repeated?737%Repeat Tests Showing Normal Results357%APA TestingTests were Repeated After 12 Weeks for Confirmation11% DisclosuresWu:Leo Pharma: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees.