Abstract
Objectives: Serological assays for SARS-CoV-2 have a critical role not only in diagnosis of COVID-19, but also in assessing the degree and duration of response of specific antibodies against the virus obtained through infection or vaccination. We present the results obtained with a competitive immunoenzymatic method (Chorus SARS-CoV-2 “Neutralizing” Ab) for quantitative determination of total neutralizing anti-S1 SARS-CoV-2 antibodies (IgG, IgM, and IgA) in human serum obtained on a disposable device with the Chorus TRIO instrument using a recombinant strong neutralizing antibody as tracer.
Methods: A total of 694 sera were evaluated for SARS-CoV-2 neutralizing antibodies: 407 uninfected, 201 symptomatic subjects, 37 post-infection patients, and 49 vaccinated. Sixty-eight of the previous sera were used to compare the Chorus SARS-CoV-2 “Neutralizing” Ab results with those obtained with micro-neutralization of the Alpha and original variants. A set of 74 positive sera for other respiratory infections were analyzed to evaluate the possible cross reaction to SARS-CoV-2 virus.
Results: Of the 694 samples, only 3 had discordant results between micro-neutralization and values measured by Chorus SARS-CoV-2 “Neutralizing” Ab: 1 false negative and 2 false positives. Values of sensitivity and specificity were very high: percent positive agreement (sensitivity) 99.6% (95% CI: 97.7 – 99.9) and percent negative agreement (specificity) 99.6% (95% CI: 98.0 -99.9). Concordance was high with a Gwet’s Ac1 of 0.992. No significant differences were observed between the alpha and original variants.
Conclusions: The Chorus SARS-CoV-2 “Neutralizing” Ab test was highly sensitive and specific, and varies from most other currently available tests since it analyzes only antibodies with viral-neutralizing capacity.
Keywords: COVID-19; Diagnostic assay; Immunoassay; Neutralizing antibodies; SARS-CoV-2.
【저자키워드】 COVID-19, SARS-CoV-2, Neutralizing antibodies, immunoassay, diagnostic assay, 【초록키워드】 respiratory infections, neutralizing antibody, SARS-CoV-2, IgG, IgM, vaccination, Neutralizing antibodies, antibody, neutralization, Infection, SARS-CoV-2 virus, virus, variants, immunoassay, sensitivity, specificity, Concordance, SARS-CoV-2 antibody, Sensitivity and specificity, cross reaction, serological assays, IgA, symptomatic, sera, Alpha, Neutralizing, respiratory, Critical, patients, human serum, SARS-CoV-2 neutralizing antibodies, specific antibodies, False negative, False positives, Post-infection, significant difference, no significant differences, 95% CI, significant differences, other respiratory infections, positive, quantitative determination, Trio, uninfected, value, tracer, Chorus, analyzed, evaluate, specific antibody, evaluated, were used, subjects, other respiratory infection, diagnosis of COVID-19, 【제목키워드】 SARS-CoV-2 neutralizing antibody, quantitative assay,