In a multicenter study a new, fully automated Roche Diagnostics Elecsys HBsAg II screening assay with improved sensitivity to HBsAg mutant detection was compared to well-established HBsAg tests: AxSYM HBsAg V2 (Abbott), Architect HBsAg (Abbott), Advia Centaur HBsAg (Bayer) Enzygnost HBsAg 5.0 (Dade-Behring), and Vitros Eci HBsAg (Ortho). A total of 16 seroconversion panels, samples of 60 HBsAg native mutants, and 31 HBsAg recombinant mutants, dilution series of NIBSC and PEI standards, 156 HBV positive samples comprising genotypes A to G, 686 preselected HBsAg positive samples from different stages of infection, 3,593 samples from daily routine, and 6,360 unselected blood donations were tested to evaluate the analytical and clinical sensitivity, the detection of mutants, and the specificity of the new assay. Elecsys HBsAg II showed a statistically significant better sensitivity in seroconversion panels to the compared tests. Fifty-seven out of 60 native mutants and all recombinant mutants were found positive. Among 156 HBV samples with different genotypes and 696 preselected HBsAg positive samples Elecsys HBsAg II achieved a sensitivity of 100%. The lower detection limit for NIBSC standard was calculated to be 0.025 IU/ml and for the PEI standards ad and ay it was <0.001 and <0.005 U/ml, respectively. Within 2,724 daily routine specimens and 6.360 unselected blood donations Elecsys HBsAg II showed a specificity of 99.97 and 99.88%, respectively. In conclusion the new Elecsys HBsAg II shows a high sensitivity for the detection of all stages of HBV infection and HBsAg mutants paired together with a high specificity in blood donors, daily routine samples, and potentially interfering sera.
A study was designed to compare an avidity index method to the serologic testing algorithm for recent human immunodeficiency virus (HIV) seroconversion (STARHS) for the detection of recent HIV infection. One hundred sixty HIV-positive sera were tested. Both techniques performed similarly in identifying recent infections, although STARHS tended to misclassify more individuals that had long-standing infection as being recently infected.
The new automated Enzymun-Test® Anti-HBc Plus for the detection of antibodies to hepatitis B virus (HBV) core antigen (anti-HBc) after pretreatment with reducing agents dithiothreitol (25°C; + DTT) or potassium bisulfite (37°C; + MBS) was evaluated by testing 571 serum and plasma samples. The panel included dilution series of reference standards and samples from chronic carriers, one seroconversion panel, samples from patients in acute or chronic stage of the disease or resolved hepatitis B, preselected sera from blood donors that were initially reactive in an anti-HBc assay without pretreatment, potentially cross-reactive serum samples obtained from patients suffering from other diseases or with passed infections other than HBV, pregnant women and individuals with HBV vaccination. The IMx CORETM (Abbott Diagnostics) served as reference assay. Discrepant samples were further investigated with two different commercial anti-HBc enzyme immunoassays, other HBV-specific serological markers and HBV DNA hybridization. The sensitivity of the Enzymun-Test Anti-HBc Plus (25°C; + DTT, and 37°C; + MBS) in comparison to the reference assay was 100%. The IMx CORE showed a twofold higher sensitivity than Enzymun-Test Anti-HBc Plus for anti-HBc detection in dilution series of serum samples from HBV carriers. The agreement in terms of specificity of the Enzymun-Test Anti-HBc Plus (25°C; + DTT, and 37°C; + MBS) and in comparison to IMx CORE was 97.4 and 96.4%, respectively. After resolution of discrepant results (3 samples were tested false negative with IMx CORE), the agreement in terms of specificity of the Enzymun-Test Anti-HBc Plus (25°C; + DTT, and 37°C; + MBS) in comparison to the combination of the comparative assays was 98.3 and 97.4%, respectively. In conclusion, the new automated Enzymun-Test Anti-HBc Plus with sample pretreatment with DTT (25°C; + DTT) or MBS (37°C; + MBS) permits a highly sensitive and specific detection of anti-HBc in diagnostic virology and blood donation testing.
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