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

  1. Sebastian L. Johnston
  2. Paul F McKay
  3. Tatiana Kebadze
  4. Kai Hu
  5. Karnyart Samnuan
  6. Juliya Aniscenko
  7. Aoife Cameron
  8. Neeta Patel
  9. Paul Randell
  10. Robin J Shattock
  11. Michael R Edwards

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Abstract

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.

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.

Funding

The development of the Virtus test and sample testing with all antibody tests was funded by Virtus Respiratory Research Ltd. The research studies providing 111 of the 208 of the “true negative” samples was supported by MRC Grant numbers MR/M025330/1 and G1100238 and by the National Institute of Health Research (NIHR) Imperial Biomedical Research Centre (BRC), SLJ is a NIHR Emeritus Senior Investigator and is funded in part by European Research Council Advanced Grant 788575 and the Asthma UK Clinical Chair (grant CH11SJ). The views expressed are those of the author(s) and not necessarily those of the NIHR or the Department of Health and Social Care.

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  1. ScreenIT

    SciScore for 10.1101/2020.10.27.20220509: (What is this?)

    Please note, not all rigor criteria are appropriate for all manuscripts.

    Table 1: Rigor

    Institutional Review Board StatementConsent: Each donor gave signed informed consent for donation of blood for service evaluation of new SARS-CoV-2 antibody testing services and for use/storage of their data.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.
    Cell Line Authenticationnot detected.

    Table 2: Resources

    Antibodies
    SentencesResources
    The Virtus quantitative antibody test to detect IgM and IgG to the SARS-CoV-2 S1 spike protein: This assay is an enzyme linked immunosorbent assay (ELISA) testing for serum antibody immunoreactivity to the SARS CoV-2 Spike S1 subunit protein.
    S1 subunit protein.
    suggested: None
    Antibodies used were goat anti-human IgM and IgG antibodies used at a dilution of 1:1000.
    anti-human IgM and IgG
    suggested: None
    The final value is the A450nM value of antibody binding to S1 antigen – no antigen A450nM value.
    S1
    suggested: None
    Experimental Models: Cell Lines
    SentencesResources
    The virus-like particles are functional and infect the Caco-2 cell line used, which expresses the SARS-CoV-2 receptor ACE2(19).
    Caco-2
    suggested: None
    Software and Algorithms
    SentencesResources
    The final 15 negative serum samples were sera from clinical test samples submitted to Virtus for commercial testing, having previously been determined negative by the Abbott Architect SARS-CoV-2 IgG antibody assay in The Doctors Laboratory commercial testing laboratory.
    Abbott Architect
    suggested: (Abbott ARCHITECT i1000sr System, RRID:SCR_019328)
    Statistical analyses were performed using Prism 7.04 (GraphPad Software).
    Prism
    suggested: (PRISM, RRID:SCR_005375)
    GraphPad
    suggested: (GraphPad Prism, RRID:SCR_002798)

    Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).

    Results from LimitationRecognizer: An explicit section about the limitations of the techniques employed in this study was not found. We encourage authors to address study limitations.

    Results from TrialIdentifier: No clinical trial numbers were referenced.

    Results from Barzooka: We did not find any issues relating to the usage of bar graphs.

    Results from JetFighter: We did not find any issues relating to colormaps.

    Results from rtransparent:
    • Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
    • Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
    • No protocol registration statement was detected.

    About SciScore

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  2. Version published to 10.1101/2020.10.27.20220509v1 on medRxiv