Evaluation of the Abbott Architect, Roche Elecsys and Virtus S1 SARS-CoV-2 antibody tests in community-managed COVID-19 cases [article]

Sebastian L Johnston, Paul F McKay, Tatiana Kebadze, Kai Hu, Kanyart Samnuan, Juliya Aniscenko, Aoife Cameron, Neeta Patel, Paul Randell, Robin J Shattock, Michael R Edwards
2020 medRxiv   pre-print
Background. Antibody testing can help define how protective immunity to SARS-CoV-2 is and how long this immunity lasts. Many antibody tests have been evaluated in hospitalised rather than community based COVID-19 cases. Virtus Respiratory Research Ltd (Virtus) has developed its own quantitative IgM and IgG SARS CoV-2 antibody assay. We report its validation and performance characteristics and compare its performance with the Abbott Architect and Roche Elecsys assays in community COVID cases.
more » ... ity COVID cases. Methods We developed a quantitative antibody test to detect IgM and IgG to the SARS-CoV-2 S1 spike protein (the Virtus test) and validated this test in 107 true positive sera from 106 community-managed and 1 hospitalised COVID-19 cases and 208 true negative serum samples. We validated the Virtus test against a neutralising antibody test. We determined sensitivities of the Abbott test in the 107 true positive samples and the Roche test in a subset of 75 true positive samples. Results The Virtus quantitative test was positive in 93 of 107 (87%) community cases of COVID-19 and both IgM and IgG levels correlated strongly with neutralising antibody titres (r=0.75 for IgM, r=0.71 for IgG, P<0.0001 for both antibodies). The specificity of the Virtus test was 98.6% for low level antibody positives, 99.5% for moderate positives and 100% for high or very high positives. The Abbott test had a sensitivity of 68%. In the 75 sample subset, the Virtus test was positive in 91%, the Roche test in 69%. Conclusions The Abbott and Roche tests had sensitives of 68% and 69% respectively in this community set of COVID-19 sera, while the Virtus test had sensitivities of 87% and 91% in the same sample sets. The strong positive correlation with virus neutralization suggests a positive Virtus quantitative antibody test is likely predictive of protective against recurrent COVID-19.
doi:10.1101/2020.10.27.20220509 fatcat:bc5i2k6dqjbmbfqz4gqwxel7ay