Combined elevation of IgM and IgA rheumatoid factor has high diagnostic specificity for rheumatoid arthritis.
Rheumatol Int
; 18(3): 119-22, 1998.
Article
in En
| MEDLINE
| ID: mdl-9833253
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.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Arthritis, Rheumatoid
/
Rheumatoid Factor
/
Immunoglobulin A
/
Immunoglobulin M
Type of study:
Diagnostic_studies
Limits:
Adult
/
Aged
/
Aged80
/
Female
/
Humans
/
Male
/
Middle aged
Language:
En
Journal:
Rheumatol Int
Year:
1998
Document type:
Article
Affiliation country:
Iceland