Abstract
The diagnostic value of measuring rheumatoid factor (RF) by agglutination or isotype-specific enzyme-linked immunosorbent assay (ELISA) was compared. The study included 70 patients with rheumatoid arthritis (RA) and 205 patients with various other rheumatic conditions. Of the RA patients, 74% were RF-positive by agglutination and 90% had one or more RF isotypes elevated by ELISA compared to 14% and 22%, respectively, of the other patients. Strikingly, 70% of the RF-positive RA patients had an elevation of two or more RF isotypes compared to only 16% of the other RF-positive patients (P<0.0001). Furthermore, a combined elevation of IgM and IgA RF was found in 52% of the RF-positive RA patients, but only in two (4%) of the other RF-positive patients (P<0.0001). It is concluded that a combined elevation of IgM and IgA RF is highly specific for RA and is very rarely found in rheumatic diseases other than RA. Isotype-specific RF assays are therefore diagnostically superior to agglutination tests. The detection of the RA-specific RF isotype pattern may be particularly helpful early in the course of RA even before the disease is fully differentiated.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
Author information
Authors and Affiliations
Additional information
Received: 10 December 1997 / Accepted: 25 June 1998
Rights and permissions
About this article
Cite this article
Jónsson, T., Steinsson, K., Jónsson, H. et al. Combined elevation of IgM and IgA rheumatoid factor has high diagnostic specificity for rheumatoid arthritis. Rheumatology International 18, 119–122 (1998). https://doi.org/10.1007/s002960050069
Issue Date:
DOI: https://doi.org/10.1007/s002960050069