Introduction We evaluated the performance of the new Abbott SARS-CoV-2 IgM assay on the Architect immunoassay analyser and compared it to the Architect IgG/Roche Cobas total antibody assays in both SARS-CoV-2 RT-PCR positive cases and healthy controls. Method 200 healthy control samples and 48 individuals with other antibody-positive disorders (18 hepatitis/18 dengue/11 ANA/1 dsDNA) served to assess for potential cross-reactivity. Anonymised residual leftover sera positive for SARS-CoV-2 on RT-PCR were recruited as cases (N = 133). The sensitivity/specificity/cross-reactivity of the Architect IgM assay were assessed. Concordance between the 3 assays were also analysed. Results There was no cross-reactivity with controls and other antibody positive samples. The Architect IgM assay was 100% specific (95% CI 98.5 to 100) and sensitivity was 77.8% (95% CI 60.8 to 89.9) ≥14 days post-first positive RT-PCR (POS). Sensitivity of the combined Architect IgM and IgG results (30.8%) was significantly better than the Cobas total antibodies (15.4%) in early disease (p = 0.04). While the Architect IgM assay had moderate agreement with the Cobas total antibody result (Cohen’s kappa 0.72), a combined Architect IgM and IgG result had better agreement (Cohen’s kappa 0.83). Conclusion The Architect IgM assay has good specificity and no cross-reactivity with other antibody positive cases. A combined Architect IgM and IgG result has better sensitivity than the individual assays for early COVID-19. The Architect IgM assay is not comparable to the Cobas total antibody assay, but the Architect IgM and IgG combined result has good agreement with the Cobas assay. Highlights • IgM/IgG may not develop in some cases of COVID-19, even ≥14 days post infection. • The sensitivity/PPV of the combined Architect IgG/IgM assays improves ≥14 days POS. • The Architect IgM/IgG combined result has good agreement with the Cobas assay. • The Architect IgM and IgG combined results slightly outperforms the Cobas assay.
【저자키워드】 antibodies, SARS-CoV-2, IgM, Assay evaluation, 【초록키워드】 COVID-19, antibody, RT-PCR, cross-reactivity, immunoassay, sensitivity, specificity, IgM/IgG, sera, Control, SARS-CoV-2 RT-PCR, antibody assay, total antibody, disease, moderate, SARS-CoV-2 IgM, positive RT-PCR, Abbott, IgM and IgG, 95% CI, healthy control, individual, healthy controls, Architect, disorder, positive, Cohen’s kappa, while, dsDNA, IMPROVE, Result, develop, significantly, recruited, evaluated, analysed, comparable, days post infection, outperform, POS, were assessed, 【제목키워드】 automated, COVID-19 antibody, chemiluminescent immunoassay, Head-to-head comparison, performance, Roche, Abbott,