Background/Purpose: The ANA by immunofluorescence is a sensitive screening test for most systemic auto-immune rheumatic diseases (SARDs). A negative result is oftentimes sufficient to exclude a diagnosis. However, when diagnostic uncertainty persists, repeat testing is sometimes performed. The utility of a subsequent positive result is not clear. Only one previous study has examined the predictive value of a subsequent positive test after an initial negative result and found that only 1.1% of such patients developed a SARD. The purpose of this study was to attempt to validate this result in a different population of patients followed longitudinally and specifically evaluated by a rheumatologist, something that had not been done previously.

Methods: All patients aged ≥18 years seen at the University of Cincinnati Medical Center who tested negative for ANA initially and subsequently tested positive and who were evaluated by a rheumatologist on one or more occasions between April 2015 and April 2024 constituted the study population. Clinical diagnoses were established by board-certified rheumatologists and independently verified through comprehensive electronic medical record review by a second rheumatologist.

Results: Of 4129 patients who underwent ANA testing and were evaluated by a rheumatologist during the study period, 296 (7.2%) had discordant results. Among these, 103 patients (2.5% of total cohort) had an initially negative ANA followed by a subsequent positive one. Records were reviewed before and after the positive result to determine if the diagnoses had been revised. In only 4 patients or 3.8% of cases did a positive result lead to a change in diagnosis. The revised diagnoses in these 4 patients were: UCTD (1), SLE (1), Sjogren’s (1), undifferentiated inflammatory arthritis (1).

Conclusion: Repeat ANA testing after a negative result in patients suspected of having connective tissue disease infrequently results in a new diagnosis. Such testing is not cost-effective and should be discouraged in clinical practice guidelines.

« Back to ACR Convergence 2025

ACR Meeting Abstracts - https://acrabstracts.org/abstract/utility-of-repeat-ana-testing/