In children, the vast majority of musculoskeletal (MSK) pain is non-inflammatory (97%) and is rarely secondary to a rheumatic disease. For patients with arthralgia (joint pain) but no arthritis on physical exam (defined as presence of joint effusion or ≥2 of warmth, tenderness, stress pain, reduced range of motion), testing rheumatoid factor (RF) or anti-cyclic citrullinated peptide (anti-CCP) is not clinically useful and has low diagnostic utility. For example, a positive RF may result from various infections. Performing such tests without clinical relevance may result in unnecessary additional testing and anxiety. For more information:
Hermosillo-Villafranca, J.A., et al., Role of rheumatoid factor isotypes and anti-citrullinated peptide antibodies in the differential diagnosis of non-selected patients with inflammatory arthralgia. Reumatol Clin. 2021. 17(1): p. 12-15. PMID: 31399351.
Wang, Y., et al., Meta-analysis: diagnostic accuracy of anti-cyclic citrullinated peptide antibody for juvenile idiopathic arthritis. J Immunol Res. 2015. 2015: p. 915276. PMID: 25789331.
Wong, K.O., et al., Antinuclear Antibody, Rheumatoid Factor, and Cyclic-Citrullinated Peptide Tests for Evaluating Musculoskeletal Complaints in Children. Comparative Effectiveness Review No. 50 (Prepared by the University of Alberta Evidence-based Practice Center under Contract No. HHSA 290 2007 10021 I). 2012, Agency for Healthcare Research and Quality: Rockville (MD). PMID: 22514802.