Diagnostic accuracy of a new fully automated chemiluminescence immunoassay for anti-SARS-CoV-2 combined IgG and IgM antibody detection

Background: Recently many serological assays for the detection of antibodies to SARS-COV-2 virus were introduced to the market. The aim of this study was to assess the diagnostic performance of a novel fully automated CLIA assay for combined (anti-IgG and IgM) anti-SARS-CoV-2 antibody detection. Methods: A total of 231 sera, 100 from consecutive patients diagnosed with COVID-19 confirmed by rRT-PCR using nasopharyngeal swabs (54 mild, 32 severe and 14 critical) and 131 controls (50 blood donors, 49 autoimmune diseases, and 32 with other viral diseases) were evaluated for combined (IgG plus IgM) anti-SARS-CoV-2 antibodies with the ADVIA Centaur® COV2T (Siemens Healthineers, Erlangen, Germany) immunoassay. In the same sera anti-SARS-CoV-2 IgM and IgG antibodies were also tested using the MAGLUMI® (SNIBE, Shenzhen, China) immunoassay. Results: Based on the manufacturer's cutoff, sensitivity, specificity, LR+, LR-, PPV and NPV of the ADVIA Centaur COV2T assay were 91% (95% CI: 83.6-95.1), 100% (97.1-100), 121.6, 0.10, 100% and 92.8%, respectively. Sensitivity of the combined antibody assay was slightly higher than that obtained by combining the results of the separate anti-IgM and anti-IgG assays (91% vs. 89% in all patients), especially in mild COVID-19 patients (85.2% vs. 81.5%). A significant difference in antibody levels (ratio) between mild and severe/critical subjects has been shown. Conclusions: The novel ADVIA Centaur COV2T assay for anti-SARS-CoV-2 combined antibody detection showed good diagnostic accuracy and, associated with the elevated automation and throughput of the system, may represent a useful tool for anti-SARS-CoV-2 antibody detection in clinical practice.