Evaluation of Multiplex Antinuclear Antibody Assay in Pediatric Patients

Objective: To determine whether multiplex antinuclear assay (ANA) can replace immunofluorescence assay (IFA) in pediatric patients. Methods: Archived frozen serum samples from patients with suspected autoimmune diseases were selected based on the availability of leftover serum samples with corresponding results. These samples had been previously tested for ANA using IFA methodology (101 samples), dsDNA (93 samples), and ENA (27 samples) by ELISA methods. Antinuclear assay screen was performed on these samples using the AtheNA Multi-Lyte ANA Test System. Results: There was a high level of discordance (45.5% concordance) between multiplex ANA screen and IFA method but strong correlation between multiplex ANA and specific autoantibody assays (89% to 96% concordance). All patients with positive ANA by IFA method, who were either diagnostic or suspicious for juvenile idiopathic arthritis (JIA), were negative by multiplex ANA assay. Conclusion: Multiplex ANA testing is an efficient and reliable method for detecting specific antinuclear antibodies; however, it cannot replace IFA as an ANA screening method in the pediatric population, especially for children with JIA.