EVALUATION OF PERFORMANCE OF THE RIBA PROCESSOR SYSTEM FOR AUTOMATED-ANALYSIS OF THE STRIP IMMUNOBLOT ASSAY FOR DETECTION OF ANTIBODIES TO HEPATITIS-C VIRUS

The performance of a new automated analyzer for the processing and int erpretation of the RIBA Strip Immunoblot Assay (SIA), used in the diag nosis of hepatitis C virus (HCV) infection, was evaluated. Laboratory performance of the RIBA SW was compared with that of two manually proc essed supplementary anti-HCV tests (RIBA HCV 3.0 SW and INNO-LIA HCV A ntibody III), Specificity of the automated processing of SIA was 100% for 90 selected anti-HCV-negative samples, On the other hand, 119 of 1 20 (99.2%) previously confirmed anti-HCV-positive samples were also po sitive when assayed on the automated processor, Results for all specim ens except one (51 of 52) were concordant for manual and automated RIB A, while 15 of 68 sera tested with automated RIBA and the INNO-LIA ass ay showed different patterns of reactivity, Three HCV sensitivity pane ls and one seroconversion panel were also compared, The results show a high sensitivity for SIA NS3- and NS5-encoded antigens, Moreover, dat a obtained for the anti-HCV seroconversion panel and for samples with borderline or discordant anti-HCV enzyme-linked immunosorbent assay re sults suggest that bands,vith a relative intensity of >0.5 on the auto mated analyzer (theoretically negative) should be evaluated with care, Coefficients of variability ranged from 9 to 14.8% in an interassay r eproducibility study. Overall, the performance of the automated analys is of SIA is comparable to that of the manual RIBA assay, The new auto mated processor for SIA bands proved to be sensitive and specific. Its use makes the optical scoring of bands unnecessary by indicating rela tive intensity values, which could be particularly useful in the follo w-up care of anti-HCV-positive patients receiving antiviral therapy.