Performance analysis of the ARCHITECT anti-cyclic citrullinated peptide antibody in the diagnosis of rheumatoid arthritis

Abstract

Background: Anti-cyclic citrullinated peptide (CCP) antibody is emerging as an important diagnostic marker for rheumatoid arthritis (RA). We evaluated the analytical and diagnostic performance of the ARCHITECT anti-CCP (Abbott Diagnostics), a new fully automated chemiluminescent microparticle immunoassay. Methods: Serum samples from 69 patients with RA and 86 non-RA patients were used to evaluate the performance of the ARCHITECT anti-CCP assay, and the results were compared with those of EliA CCP (Phadia). The optimal cut-off value was calculated using receiver operating characteristic (ROC) curve analysis. Results: Within-run and total imprecision (%CV) of the ARCHITECT anti-CCP were < 6% and good linearity was observed over the claimed range. The areas under the ROC curves for the ARCHITECT anti-CCP and EliA CCP were 0.90 and 0.89, respectively. The sensitivity and specificity were 76.8% and 95.3% for the ARCHITECT anti-CCP and 78.3% and 95.3% for EliA CCP using the manufacturer`s cut-off thresholds. Both assays showed sensitivity of 84.1% and specificity of 94.2% using the optimal cut-off values. Conclusions: The analytical performance of the ARCHITECT anti-CCP was satisfactory and diagnostic performance was comparable to that of EliA CCP. The use of optimal cutoff thresholds can yield higher sensitivity with minimal loss of specificity. Clin Chem Lab Med 2010;48: 225-30.