Evaluation of the AxSYM HCV version 3.0: Improved Performance of a newly developed HCV assay

Objective: The performance of the newly developed, rapid and fully automated assay AxSYM HCV version 3.0 designed for the detection of antibody to HCV was evaluated with respect to precision, sensitivity and specificity in parallel to the Abbott HCV EIA 3.0 assay. Results were also compared to the previous AxSYM HCV assay. Assay Design: The AxSYM HCV version 3-0 is an automated microparticle immunoassay which allows the early detection of antibody to hepatitis C virus. Utilizing recombinant HCV proteins (core, NS3, NS4 and NS5) bound to microparticles, anti-HCV antibodies are identified via anti-human IgG detection. Assay Performance Evaluation: Precision: The reproducibility of the AxSYM HCV version 3.0 was determined using anti-HCV positive member panels (n=5) including the Index Calibrator and Run Control of the kit. Depending on the panel member and based on up to 72 individual observations, the %CV ranged between 5.54%-7.18% for intra-assay and between 6.44%-7.52% for inter-assay runs. Specificity: Three different blood donor specimen populations obtained from volunteer donors and pre-screened with HCV 2nd Generation assays were used to determine the specificity of the assay. Among a total of 4,383 specimens (2,258 serum & 2,125 plasma specimens) the AxSYM HCV version 3.0 showed a specificity of 99.84% (4,374/4,381). On the same specimen populations, the Abbott HCV EIA 3.0 revealed a specificity of 99.8% (4,372/4,381). In comparison, the specificity of the current Abbott AxSYM HCV assay had been estimated to be 99.69%. Sensitivity: Sequential specimens represented in 20 available seroconversion panels were used for assessing sensitivity. When compared to other HCV antibody detection assays (e.g. HCV EIA 3.0, HCV EIA 2.0), the AxSYM HCV version 3.0 detected seroconversion earlier in up to 10 panels (5× 1 bleed, 5×2 bleeds), at the same time in 9 panels, and in one case 1 bleed later. Conclusion: Based on the seroconversion sensitivity in combination with the improved specificity, the AxSYM HCV version 3.0 appears to be a highly useful tool for the detection of antibody to HCV in blood donor testing.