B-165 Evaluation of a newly developed Access anti-HAV IgM immunoassay on the DxI 9000 Immunoassay Analyzer in the United States

Abstract

Background Beckman Coulter, Inc. recently developed a fully automated Access anti-hepatitis A Virus (HAV) IgM assay for the detection of IgM antibodies to HAV for use on the DxI 9000 Immunoassay Analyzer. The assay's analytical and clinical performances were evaluated. Methods Imprecision was evaluated using three replicates of eight samples including serum and plasma and two quality controls using multiple reagent packs and calibrator lots in 40 runs based on CLSI EP05-A3. Reproducibility was evaluated at three U.S clinical laboratories using one lot of reagent, with low and high negative and positive serum and plasma samples, and quality controls based on CLSI EP05-A3. Cross-reactivity was evaluated using 348 negative samples and a reference method across 25 categories including other viral infection and auto-immune diseases. Seroconversion panels were tested to evaluate sensitivity of the Access anti-HAV IgM Assay in early detection of hepatitis A IgM antibodies. Clinical performance on the DxI 9000 Analyzer was evaluated in comparison to commercially available FDA-cleared anti-HAV IgM reference assays at three U.S clinical laboratories to evaluate the assay’s ability as an aid in the diagnosis of acute or recent HAV infection. Results Within-Laboratory imprecision demonstrated = 7.7 % CV for samples = 1.00 S/CO, and standard deviation (SD) = 0.05 for samples < 1.00 S/CO while reproducibility demonstrated an overall imprecision = 8.8% for samples = 1.00 S/CO (n=360) and an SD of = 0.05 for samples < 1.00 S/CO (n=360). The cross-reactivity study demonstrated overall negative agreement of 100.0% versus the reference assay. In seroconversion testing, the Access anti-HAV IgM assay exhibited sensitivity equivalent to the reference assay across three panels, notably detecting anti-HAV IgM one bleed earlier on a fourth panel. The Access anti-HAV IgM assay demonstrated overall PPA of 100.0% (n=88/88; 95% CI: 95.8-100.0%) and NPA of 99.3% (n=762/767; 95% CI: 98.5-99.7%) in the diagnostic population. Conclusion The Access anti-HAV IgM assay consistently demonstrated excellent analytical and clinical performance, proving equivalent to currently FDA-cleared anti-HAV IgM assays. Given the recent shift in US hepatitis A outbreaks1 from predominantly food-borne to person-to-person transmission, the introduction of a new, high-throughput anti-HAV IgM assay is particularly significant, enabling robust and scalable serologic testing crucial for effective public health surveillance and outbreak management.