All issues > Volume 35(5); 1992

Original Article

J Korean Pediatr Soc. 1992;35(5):639-645. Published online May 15, 1992.

Clinical Significance of Rheumatoid Factor in Juvenile Rheumatoid Arthritis

Ki Joong KJ Kim¹, Bo Young BY Yun¹, Joong Gon JG Kim¹

¹Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea

Abstract

Rheumatoid factor is a commonly used laboratory test by clinicians to assess the children with possible juvenile rheumatoid arthritis. To assess its diagnositc value and clinical significance we reviewed the case histories of the patients in whom latex agglutinating rheumatoid factor was tested during November 1988 to April 1991 at Seoul National University Children's Hospital. There were 61 patients with positive test for rheumatoid factor, of whom 16 had juvenile rheumatoid arthritis. A total of 813 children had negative results, of whom 63 had juvenile reheumatoid arthritis. This yields a sensitivity of 20.3% and a specificity of 94.3%. The predictive values and marginal benefits for rheumatoid factor were calculated using Bayes' theorem. Rheumatoid factor testing appeared to be of few benefit. The clinical and laboratory data were obtained from 14 patients with positive results and 48 patients with negative results to assess the clinical significance. There were no significant difference between rheumatoid factor positive and negative patients in clinical findings including age of onset, sex, type of disease, and articular and extraarticular manifestation, and laboratory findings of inflammatory indices such as WBC count, platelet count, ESR, CRP, ASO, FANA and bone X-ray. Testing for rheumatoid factor seems to be a poor screening procedure for juvenile rheumatoid arthritis in the general situation.

Keywords :Rheumatoid factor, Juvenile rheumatoid arthritis