Using Antinuclear Antibody Testing in Pediatric Rheumatology

The antinuclear antibody (ANA) test is frequently used for the identification of patients who are at a high risk of developing autoimmune rheumatological diseases. The aim of this study is to evaluate the final diagnoses of patients applied to the pediatric rheumatology outpatient clinic with a positive ANA test result. In this study, the medical records of 283 children who had ANA positivity between January 2010 and January 2022 were evaluated retrospectively. All patients were younger than 18 years of age at diagnosis and were followed up in the pediatric rheumatology department for at least 6 months. The majority of the patients were females (69%), and the mean age was 9.9 +/- 4.7 years. 94% of the ANA tests were requested in pediatric rheumatology outpatient clinics, and 6% in general pediatrics and other outpatient clinics. Arthritis was the most common reason for ANA testing (41.7%). Of the patients who had ANA positivity, 37% were diagnosed with juvenile idiopathic arthritis (JIA), 15% with connective tissue diseases, 10% with autoinflammatory disease, and 7% with vasculitides. Positivity at 1/320 and 1/640 titers were more common in the patients diagnosed with autoimmune connective tissue diseases or JIA compared to the patients without these diagnoses (P = .009 and P = .013, respectively). The ANA test should be judiciously requested by pediatric rheumatologists, especially in suspected cases of autoimmune rheumatic disorders and JIA patients to aid in classification. Indiscriminate use of the ANA test for screening may potentially misguide clinicians.