J Lab Med Qual Assur.  2005 Jun;27(1):195-202.

Diagnostic Performance of the Anti-Cyclic Citrullinated Peptide Antibodies and Rheumatoid Factor Isotypes in Rheumatoid Arthritis

• Kim KH
• Kwon JA
• Kim YK

Abstract

BACKGROUND: The rheumatoid factor (RF) is the only serological marker in American College of Rheumatology criteria for the diagnosis of rheumatoid arthritis (RA), but its specificity is not satisfactory for the diagnosis of RA. We evaluated the diagnostic performance of a new anti-cyclic citrullinated peptide antibodies (anti-CCP) test with those of RF isotypes for the diagnosis of RA.
METHODS
Anti-CCP was determined in 186 serum samples: 110 from RA patients, 30 from non-RA patients(rheumatic diseases other than RA), and 46 normal individuals. IgM RF by latex fixation test and IgA RF by ELISA were also assayed in each samples, and the results were compared to anti-CCP for sensitivity and specificity by the receiver-operating characteristic curve on optimal cut-off values.
RESULTS
The sensitivity of anti-CCP was highest (80.0%) and the sensitivities of IgM RF, IgA RF were 71.8%, 45.5%, respectively. The sensitivity increased (from 80.0% to 88.2%) especially in the combination of anti-CCP with IgM RF. The specificity of IgA RF by ELISA were highest (96.0 %) and the specificity of anti-CCP (94.7%) was higher than that of IgM RF (71.4%). Anti-CCP was positive in 58.1% in 31 RA patients with negative IgM RF.
CONCLUSIONS
The results said that the combination test of anti-CCP with IgM RF might be useful for the diagnosis of RA because of its higher sensitivity and specificity than IgM RF alone.

Keyword

Anti-cyclic citrullinated peptide antibodies; rheumatoid factor; rheumatoid arthritis

MeSH Terms

Antibodies*
Arthritis, Rheumatoid*
Diagnosis
Enzyme-Linked Immunosorbent Assay
Humans
Immunoglobulin A
Immunoglobulin M
Latex Fixation Tests
Rheumatoid Factor*
Rheumatology
Sensitivity and Specificity
Antibodies
Immunoglobulin A
Immunoglobulin M
Rheumatoid Factor