Automated Determination of Citrullinated Cyclic Peptide Antibodies on AxSYM Analyser
a Department. of Clinical Laboratories, Hospital, Klatovy, b Department of Clinical Pharmacology, University Hospital, Plzeň, c Department of Social Medicine, Faculty of Medicine, Charles University, Plzen
The aim of the study was to verify reproducibility, limit of detection, reference limits and diagnostic value of a new antiCCP2 method ? AxSYM® Xtra Anti-CCP as a marker of rheumatoid arthritis. Reference limits were verified on a group of 105 volunteers. Diagnostic performance was assessed in a group of 95 patients with rheumatoid arthritis and 75 patients with systemic connective tissue diseases or polyarthritis. The AxSYM® Xtra Anti-CCP assay achieved the day-to-day reproducibility 5.0?5.3 %, the detection limit was 0.8 U ml?1. The assay reached 71 % and 53 % diagnostic sensitivity at 95 % and 100 % diagnostic specificity with cut-off 2.0 U/ml and 5.0 U ml?1, respectively. We found also 4.2 % of positive values in systemic connective tissue diseases above the cut-off 5.0 U ml?1. The AxSYM® Xtra Anti-CCP assay provides automated random access measurement of anti-CCP antibodies with good analytical performance and diagnostic sensitivity and specificity comparable with other methods.
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