Analytical and diagnostic performance of an automated anti-CCP assay.
OBJECTIVE
Autoantibodies against cyclic citrullinated peptide (anti-CCP) are considered to be a sensitive and specific marker for rheumatoid arthritis (RA). This study evaluated the diagnostic and analytical performances of the automated anti-CCP assay.


METHODS
Sera from 80 patients with established RA, 65 from other rheumatic diseases (non-RA) and 55 from healthy controls were studied using second generation anti-CCP. Rheumatoid factor (RF) was also assayed in each sample, and the results were compared to the anti-CCP findings. Serum pools were used to determine the precision and linearity.


RESULTS
At a cut-off of 7.4 U/ml for anti-CCP, the sensitivity and specificity for RA were 65% and 98% respectively. RF had a sensitivity of 58% and a lower specificity of 93% than anti-CCP.


CONCLUSIONS
The high specificity of the assay suggests that anti-CCP is useful in the diagnosis of rheumatoid arthritis and in our cohort of study population anti-CCP exhibits a better diagnostic value than RF. A considerable proportion (28%) of RF-negative RA patients were anti-CCP positive. Based on analytical performance of the assay, we conclude that full automation and high throughput features of AxSYM makes it an ideal platform for routine testing of anti-CCP.
Department of Pathology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
Sthaneshwar
S
Pavai
Sokkalingam
S
Sargunan
Amir Azlan
AA
Zain
Sook-Khuan
SK
Chow
D019540:Area Under Curve; D001172:Arthritis, Rheumatoid / Q000097:blood / Q000175:diagnosis* / Q000276:immunology; D001323:Autoantibodies / Q000032:analysis* / Q000097:blood; D001774:Blood Chemical Analysis / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D010456:Peptides, Cyclic / Q000276:immunology*; D012372:ROC Curve; D012680:Sensitivity and Specificity
D001323:Autoantibodies; D010456:Peptides, Cyclic; C487763:cyclic citrullinated peptide