Clinical Significance of Positive Antinuclear Antibody Tests in Adults at a Tertiary Care Hospital

Introduction: Antinuclear antibody (ANA) positivity is not limited to autoimmune pathology; it can be present in a variety of non-autoimmune illnesses as well as healthy individuals. The purpose of this study is to elucidate the clinical significance of positive ANA in adults in a hospital setting. Materials and Methods: A retrospective, record-based study was conducted in Seer Central Hospital, targeting adult patients aged 18 years and above who tested positive for ANA between January 2018 and December 2022. Descriptive statistics were used to summarize the data, and a chi-square test was used to determine if the distribution of disease categories differed significantly between high (≥640) and low (≤160) ANA chter groups. Results: Out of 2141 individuals who underwent an ANA test, 578 (27%) tested positive. Of the 578 ANA-positive individuals, 39.6% had ANA-associated rheumatic diseases (AARDs), 27% other autoimmune diseases, 2.1% malignancies, 3.6% infections, 12.6% other diagnoses, 10.2% no identifiable disease, and 4.8% unknown. Systemic lupus erythematosus was the most prevalent AARD (85.2%). AARDs occurred in 77.5% of high ANA titer cases (≥640) versus 18.9% of low titer cases (≤160), indicating a strong predictive value for AARDs ( P < 0.001). Conclusion: Positive ANA can be detected in a wide range of rheumatic and non-rheumatic disorders. Subsequently, our findings show the importance of evaluating ANA results within a comprehensive clinical framework, rather than relying solely on serological data. High ANA titers demonstrated a strong correlation with AARDs, emphasizing the importance of titers in recognizing these conditions in tertiary care settings.