[Diagnostic utility of AxSYM anti-cyclic Citrullinated peptide antibody assay].
BACKGROUND
The presence of rheumatoid factor (RF) is one of the classification criteria of the American College of Rheumatology (ACR) for rheumatoid arthritis (RA), but it has a limitation of low specificity. We compared the diagnostic utility of anti-cyclic citrullinated peptide (CCP) antibodies analyzed by an automated immunoassay system with that measured by a 96 well plate ELISA method.


METHODS
The RF and anti-CCP antibodies were determined in 172 serum samples: 52 RA patients, 73 disease controls (systemic lupus, Sjogren's syndrome, palindromic rheumatism), and 47 healthy controls. Anti-CCP antibodies were measured by DIASTAT 96 well plate ELISA method (Axis-Shield Diagnostics, UK) and AxSYM automated microparticle enzyme immunoassay system (Abbott Laboratories, USA). RF was assayed by latex immunoturbidimetry (Toshiba 200 FR, Japan). The diagnostic performances of these tests were compared using a ROC curve analysis, and linearity and precision analysis of AxSYM anti-CCP was carried out.


RESULTS
The sensitivities of RF, DIASTAT anti-CCP, and AxSYM anti-CCP were 78.8%, 84.6%, and 82.7%, respectively and the specificities were 72.5%, 88.3%, and 88.3%, respectively. On ROC curve analysis, the area under the curve was 0.924 for AxSYM anti-CCP, 0.886 for DIASTAT anti-CCP, and 0.847 for RF. AxSYM anti-CCP showed a good linearity, and within-run and total-run precision.


CONCLUSIONS
Diagnostic performance of automated AxSYM anti-CCP assay was comparable to that of DIASTAT 96 well plate ELISA method. AxSYM anti-CCP assay has an advantage of random access capability and will be useful in laboratories with low sample number and/or with a need of rapid turnaround time.
Kim
Kyung-Eun
KE
Department of Laboratory Medicine, Dong-A University College of Medicine, Busan, Korea.
Kim
Kyeong-Hee
KH
Woo
Kwang-Sook
KS
Han
Jin-Yeong
JY
Kim
Jeong-Man
JM
Lee
Sung Won
SW
Chung
Won Tae
WT
D000293:Adolescent; D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000175:diagnosis*; D001323:Autoantibodies / Q000097:blood*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D008875:Middle Aged; D010456:Peptides, Cyclic / Q000276:immunology*; D012372:ROC Curve; D011933:Reagent Kits, Diagnostic; D012217:Rheumatoid Factor / Q000097:blood; D012680:Sensitivity and Specificity
D001323:Autoantibodies; D010456:Peptides, Cyclic; D011933:Reagent Kits, Diagnostic; C487763:cyclic citrullinated peptide; D012217:Rheumatoid Factor