Don’t order rheumatoid factor alone, or as part of a “panel” or “cascade” in children to evaluate for rheumatologic disease such as juvenile idiopathic arthritis due to musculoskeletal complaints. Don’t let laboratory results guide referral.
|Rationale and Comments:||Juvenile idiopathic arthritis is a clinical diagnosis, and laboratory studies are used to prognosticate severity. Only 10% to 30% of children with juvenile idiopathic arthritis have a positive rheumatoid factor compared to the majority of adults with rheumatoid arthritis. The relevance of other antibodies such as anti-cyclic citrullinated peptide has not been established in the pediatric population. Additionally, rheumatoid factor is nonspecific and can be positive in other diseases, infections, or healthy individuals, and these labs are typically expensive. Patients may still have juvenile idiopathic arthritis despite a negative rheumatoid factor, and a positive test with no clinical disease causes significant parental anxiety and may result in additional unnecessary testing.|
|References:||• Groot N, Heijstek M, Wulffraat N. Agarwal M, Sawhney S. Laboratory tests in pediatric rheumatology. Indian J Pediatr. 2010;77(9):1011–6.
• Dalrymple A. Laboratory evaluation in pediatric autoimmune disease. Pediatr Rev. 2015;36(11):496.
• Ingegnoli F, Castelli R, Gualtierotti R. Rheumatoid factors: clinical applications. Hindawi. 2013;35(6):727–34.
• Smolen, Josef S, Aletaha, Daniel, McInnes, Iain B. Rheumatoid arthritis. The Lancet. 2016;338(10055):2023-2038.
• Wong KO, Bond K, Homik J, Ellsworth JE, Karkhaneh M, Ha C, Dryden DM. 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). AHRQ Publication No. 12-EHC015-EF. Rockville, MD: Agency for Healthcare Research and Quality. March 2012. Effectivehealthcare.ahrq.gov/reports/final.cfm.