Ab1044 Positive Ana Testing in an Academic Medical Center: Impact on Diagnosis

Background: sAnti-nuclear antibodies (ANA) are common in systemic rheumatic diseases, non-rheumatic autoimmune diseases and the general population. In clinical practice, testing for ANA can inform further clinical diagnoses even in the absence of symptoms to suggest SLE or connective tissue disease. This study was undertaken to evaluate whether ANA testing result informed clinical diagnosis. Objectives: 1). Determine the frequency of ANA testing in an academic medical center, 2). Determine the demographics and principal diagnoses of people undergoing ANA testing in an academic medical center, and 3) Determine the impact of positive ANA determinations on diagnosis and patient care. Methods: The UT Southwestern Medical Center IRB approved this study. Data were obtained by SQL queries of the Epic electronic health record. The study population included all patients for whom an ANA was ordered at UT Southwestern Medical Center January 1, 2010 to June 30, 2017. The titer and pattern of the ANA as well as the results of ENA or anti-dsDNA testing were documented. Patient characteristics included age and sex. Encounter characteristics included the date of testing, frequency of testing, primary encounter diagnosis, and provider specialty. Chart review was performed by a board-certified rheumatologist in patients who had a change in diagnosis after a positive ANA. Results: During the study period, a total of 33,270 ANA tests were ordered in 28,659 unique patients. 22,529 of the ANAs were tested in outpatients, representing 0.7% of all office visits during this time. Forty-nine percent of the ANA tests were positive at a titer of 1:80 or greater; slightly more women (51%) had a positive ANA (≥1:80) than did men (43%). 54.5% of the positive ANA in women were 1:320 or greater vs. 41.6% in men (pConclusion: ANA testing in the inpatient and outpatient setting is common. Diagnoses precipitating testing are most often non-rheumatic conditions. A positive ANA result changed the clinical diagnosis in a small percentage of patients and rarely informed treatment. REFERENCES: NIL. Acknowledgements: NIL. Disclosure of Interests: David Karp Support to university from UCB, Eli Lilly, Genentech, Bristol-Myers Squibb, Novartis, and Biogen., Bonnie Bermas: None declared, Shivani Kottur: None declared.