Evaluation of the new multiplexed immunoassay, fidis, for simultaneous quantitative determination of antinuclear antibodies and comparison with conventional methods

Our study was done to evaluate the FIDIS Connective kit (Biomedical Diagnostics, Marne la Vallée, France) for simultaneous quantitative determination in the same sample of 9 antinuclear antibody specificities directed against double-stranded DNA, SSA, SSB, Sm, Sm/RNP, Scl-70, Jo-1, ribosome, and centromere B and to compare it with standardized commercial methods, enzyme immunoassay and immunofluorescence. FIDIS technology constitutes a new multiplexed method using the Luminex 100 system (Luminex, Austin, TX) based on the use of distinct color-coded particles and flow cytometric detection. Serum samples from people with diagnosed rheumatic diseases with well-identified markers of autoimmunity were tested by a retrospective study. Specificity was assessed by testing blood donors and potential biologic interfering samples. This first evaluation demonstrated the analytic performance of FIDIS technology. Concordances with routine methods were between 99.1% and 100.0% on 222 samples. FIDIS was reliable (coefficients of variation < 10%) and accurate (correlation coefficients with enzyme-linked immunosorbent assay between 0.90 and 0.97) in a large measure range.