Dosage automatisé des anticorps anti-peptides cycliques citrullinés (anti-CCP) sur l'analyseur Elecsys®: validation analytique et valeur diagnostique

Abstract

Anti-cyclic citrullinated peptides (anti-CCP) are highly characteristics of rheumatoid arthritis (RA). Since 2006, anti-CCP assays have been included in both French and European recommendations. We have evaluated the analytical and clinical performances of the anti-CCP assay on the Elecsys analyzer (Roche Diagnostics). Two plasma pools (target values: 17.2 and 363.0 U/mL) and two quality controls (target values: 24.5 and 157.0 U/mL) were tested; we also analyzed three hundred plasma samples from healthy subjects (n = 86) and diseased patients (presenting with RA, non rheumatoid disorders, or undifferentiated arthritis: n = 214). Analytical performances (intra- and inter-assay precisions) and clinical performances (ROC analysis and method comparison) were evaluated. Elecsys assay was compared to Immunoscan RA(R) assay using contingency tables. Intra- and inter-assay precisions showed coefficients of variation less than 5%. ROC analysis showed an area under the curve at 0.886. Considering the value of 17 U/mL as the optimal cut-off, we found sensibility and specificity at 75% and 95%, respectively. Comparison of the Elecsys anti-CCP assay with the Immunoscan RA(R) assay showed an overall agreement of 98,3%. We conclude that the the Elecsys anti-CCP assay displayed a high precision and clinical performances comparable to that of the efficient anti-CCP assay Immunoscan RA(R).