Comparison of three anti-CCP antibody tests and rheumatoid factor in RA and control patients

It was the aim of this study to compare the diagnostic properties of two second generation anti-CCP antibodies assays (Quanta Lite CCP, Inova and EliA CCP, Phadia) with an assay containing a new antigen mixture (Quanta Lite CCP 3, Inova) and RF IgM.

Sera from 86 RA patients and 90 control patients with other diseases, such as infections, connective tissue diseases, or other rheumatic diseases, were analysed using the four different methods. Specificity (84.4%) and PPV (80.3%) were lowest for RF IgM and highest for EliA CCP (specificity 97.8%, PPV 96.7%), the other values being close to those of EliA CCP. Sensitivity was highest for Quanta Lite CCP (73.3%). Efficiency was highest for Quanta Lite CCP (84.1%) at the lower cut off followed by EliA CCP at both cut offs (83.0%). The discrimination between RA sera (mean value 407.67 U/ml) and control sera (4.54 U/ml) and the relative risk (23.34) were best for EliA CCP. The results of this study reveal that there was no advantage of the anti-CCP antibodies assay applying a new antigen mixture (Quanta Lite CCP 3 ELISA) compared to two second generation anti-CCP antibodies assays (Quanta Lite CCP ELISA and EliA CCP).