%0 Journal Article %A Emily G. Ferrell %A Lori A. Ponder %A Lauren S. Minor %A Sheila T. Angeles-Han %A Christine W. Kennedy %A Kelly A. Rouster-Stevens %A Mina Rohani-Pichavant %A Larry B. Vogler %A Sampath Prahalad %T Limitations in the Classification of Childhood-onset Rheumatoid Arthritis %D 2014 %R 10.3899/jrheum.130563 %J The Journal of Rheumatology %P 547-553 %V 41 %N 3 %X Objective. Rheumatoid factor-positive polyarthritis (RF+ poly) is the juvenile idiopathic arthritis (JIA) category that resembles adult seropositive rheumatoid arthritis (RA). We studied children with RF+ and/or anticyclic citrullinated peptide antibody (anti-CCP)+ JIA to determine what proportion of those children meet International League of Associations for Rheumatology (ILAR) criteria for RF+ poly JIA and to assess for significant differences between children who meet RF+ poly criteria and those who are classified in other categories. Methods. Charts of children with JIA who were RF+ and/or anti-CCP+ were reviewed. Children with RF+ poly JIA were compared to children in other categories. Statistical analysis was performed using chi-square, Fisher’s exact test, and the Student’s t-test. Results. Of 56 children with RF+ and/or anti-CCP+ JIA, 34 (61%) met ILAR criteria for RF+ poly JIA. Twelve children had RF–/anti-CCP+ JIA with low anti-CCP titers. When these 12 children were excluded, there were few significant differences between children who met criteria for RF+ poly and those who were classified in other categories. The American College of Rheumatology/European League Against Rheumatism criteria for RA identified more RF+ children than did the ILAR RF+ poly classification (100% vs 77%). Conclusion. A number of children with RF+ arthritis were excluded from the RF+ poly JIA classification, though many demographic features and disease measures were similar to those of children who met criteria for RF+ poly JIA. We propose prioritization of RF/anti-CCP positivity over specific exclusions, along with inclusion of anti-CCP, in future revisions of the JIA classification criteria, to improve the sensitivity of diagnosing childhood-onset RA. %U https://www.jrheum.org/content/jrheum/41/3/547.full.pdf