Evaluation of Antinuclear Antibody and Subserology Reflex Testing for the Diagnosis of Systemic Autoimmune Rheumatic Disorders in an Academic Teaching Hospital

Abstract

Abstract Objective The aim of this study was to examine appropriate utilization of antinuclear antibody (ANA) screening tests with follow-up subserology tests (reflex testing) for diagnosing systemic autoimmune rheumatic disorder (SARD). Methods We conducted a retrospective chart review of 3003 SARD-test orders at an academic teaching hospital from January to December 2019. Testing patterns were categorized as American College of Rheumatology (ACR)-recommended reflex testing, panel testing, or single subserology testing. We described testing patterns, assessed their diagnostic accuracy, and explored factors associated with reflex testing. Results Reflex testing accounted for 79.7% of SARD test-ordering, whereas improper testing (panel or single subserology) accounted for the other 20.3%. Reflex testing was associated with significantly more SARD diagnoses than improper testing (P = .004). Testing patterns were significantly associated with race/ethnicity (P = .008), with reflex testing being less frequent than improper testing in Hispanics and Whites. Conclusion In summary, one-fifth (20.3%) of testing patterns for suspected SARD did not follow the ACR-recommended guidelines for using reflex testing. Use of reflex testing was associated with an increased frequency of SARD diagnosis.