ANA multiplex testing overutilized, 'straying further' from Choosing Wisely guidelines
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Contrary to Choosing Wisely recommendations, indiscriminate and high use of antinuclear antibodies multiplex testing has fostered widespread unfamiliarity of what it tests for and how to interpret its results, noted a presenter here.
“The presence of antinuclear antibodies (ANA) is a key step in the initial diagnosis of several autoimmune rheumatic diseases, such as lupus and mixed connective tissue disease (CTD), as well as several nonrheumatic conditions such as autoimmune hepatitis,” Hamish Patel, MD, a rheumatology fellow at Brooke Army Medical Center in San Antonio, told attendees at the 2021 North American Young Rheumatology Investigator Forum.
Although the gold standard for measuring ANAs remains the immunofluorescence test, which is fairly sensitive, newer, automated and less expensive assays, such as the enzyme linked immunoassays (ELISA) and the multiplex or solid phase bead assays, have been developed and have come into widespread use.
In response to the growing use of ANAs, in 2015, in concert with the American Board of Internal Medicine’s Choosing Wisely campaign, the American College of Rheumatology first published its Top 5 Choosing Wisely recommendations.
“Its first recommendation basically stated, ‘do not test sub-serologies without a positive ANA or clinical suspicion,’” Patel said.
To determine whether the Choosing Wisely guidelines have curtailed inappropriate use of ANA multiplex assays at a single center, Patel and colleagues examined the total number of ANA multiplex tests ordered in single year, patient demographics, initial reason for ordering the ANA, the service that ordered the test, the different positive components on the multiplex panel, referral to a rheumatologist and final diagnosis.
According to study results, from January 1, 2020, to December 31, 2020, approximately 5,928 ANA multiplex tests were ordered, of which 6.4% exhibited at least one positive result (n=382) from a population of 322 patients. Of this group, 88 patients were already diagnosed with CTD; 41.8% of the 234 remaining patients were referred to rheumatology, with 27 patients later receiving a CTD diagnosis, including systemic lupus erythematosus (n=9) Sjögren’s syndrome (n=6), scleroderma (n=3), undifferentiated CTD (n=3), discoid lupus (n=1), vasculitis (n=1), giant cell arteritis (n=1) a myositis (n=1).
“In this single-center study, we saw that ANA multiplex was ordered a lot in a single-year period,” Patel told attendees. “Over 96.3% of individuals were negative, and only 0.46% were determined to have a new autoimmune rheumatic disease diagnosis.”
Patel noted that the ANA multiplex tests were most frequently ordered by primary care physicians, often “for non-specific reasons, such as pain and rash,” whereas among specialty providers, 54.9% were ordered by gastroenterology for “the evaluation of elevated LFTs.”
“This more frequent utilization demonstrates gaps in understanding about not only the test characteristics but what the test is specifically testing for, as well as an unfamiliarity with how to interpret the results,” Patel said. “These results also demonstrate that we’re straying further from the Choosing Wisely guidelines and recommendations in that we’re ordering a test that tests for secondary and sub-serologies first before looking at the actual ANA.”
He added: “Contrary to the initial intentions of the multiplex assay, our study demonstrates that the inherent advantages of the test – its rapidity, its affordability and its availability – are actually its downfall, because it leads to greater utilization without clear understanding.”
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Patel HR. Evaluation of the Multiplex Antinuclear Antibody Test as an Inappropriate Initial Screening Tool. Presented at: North American Young Rheumatology Investigator Forum; August 11, 2021; Destin, Fla. (hybrid meeting).
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