Half of all thrombophilia tests were considered inappropriately ordered in a retrospective study presented at the 63rd ASH Annual Meeting & Exposition.

“Despite society recommendations to limit thrombophilia testing, this testing is often sent inappropriately,” researchers explained.

In an effort to better understand what leads to unnecessary testing, authors conducted a laboratory query of thrombophilia testing at LAC+USC Medical Center from January 1, 2019 to December 31, 2019 during which electronic medical records were reviewed for clinical history, testing indication, requesting service, and appropriateness. Patients who had undergone testing for thrombophilia without a confirmed diagnosis were eligible for inclusion in the retrospective study.

Testing included Factor V Leiden (FVL) and prothrombin 20210 gene mutations; activated protein C resistance; antithrombin or protein C or S activity levels; antiphospholipid syndrome evaluation with lupus anticoagulant, cardiolipin immunoglobulins IgM/G, and beta-2 glycoprotein IgM/IgG; and JAK2 V617F mutation.

Tests that were considered unnecessary or of limited clinical value were homocysteine levels, methylenetetrahydrofolate reductase gene mutation, FV activity, and phosphatidylserine IgM/IgG. Inappropriate testing criteria also included provoked venous thromboembolism (VTE) and stroke/transient ischemic attack (TIA).

Researchers also noted, “For unprovoked VTE, testing was considered inappropriate for patients >45 [years old] except for [antiphospholipid syndrome (APS)] testing. For nonstroke arterial thrombosis, recurrent pregnancy loss or stillbirth, and diagnostic evaluation of suspected lupus, APS testing only was considered appropriate.”

The final study sample included 450 patients of mean 42 years of age (range 18-90) who were mostly female (76%) and Hispanic (81%). During the study period, 1698 tests were sent by 27 services from inpatient (40%), outpatient (59%), and emergency department (1%) settings. The average number of tests per patient was 3.7.

Tests were most commonly requested by rheumatology (24%), obstetrics–gynecology (19%), internal medicine/medicine–pediatrics (14%), and and hematology (10%) services. The most common indications for testing were VTE (21%), rheumatology (25%), and pregnancy (13%).

A total of 840 tests (49%) were designated inappropriate. Some common reasons for inappropriate testing included:

• provoked VTE events;
• stroke/TIA;
• APS testing after first pregnancy loss;
• duplicate testing;
• incomplete testing;
• incorrect tests;
• repeat testing less than 12 weeks from previous test; and
• issues with APS and FVL testing.

Authors noted that inappropriately ordered tests are a “relatively common issue, particularly with APS and FVL testing.”

"It is unlikely that physician education alone will lead to a substantial or sustained decrease in the number of inappropriate tests," researchers wrote. "Rather, it may be necessary to restrict at least some thrombophilia testing to certain services."

Reference:
Chow L, Garvey S, Ma T, Hudgins J, Piatek CI. Ordering patterns of thrombophilia testing and its appropriateness. Poster presented at: 63rd ASH Annual Meeting & Exposition; December 11-14, 2021: Atlanta, GA.