Validation of a commercially available SARS-CoV-2 serological immunoassay

  1. B. Meyer
  2. G. Torriani
  3. S. Yerly
  4. L. Mazza
  5. A. Calame
  6. I. Arm-Vernez
  7. G. Zimmer
  8. T. Agoritsas
  9. J. Stirnemann
  10. H. Spechbach
  11. I. Guessous
  12. S. Stringhini
  13. J. Pugin
  14. P. Roux-Lombard
  15. L. Fontao
  16. C.-A. Siegrist
  17. I. Eckerle
  18. N. Vuilleumier
  19. L. Kaiser

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Abstract

No abstract available

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  1. Version published to 10.1016/j.cmi.2020.06.024
  2. ScreenIT

    SciScore for 10.1101/2020.05.02.20080879: (What is this?)

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

    Table 1: Rigor

    Institutional Review Board StatementIRB: Ethical approval for all sera used in this study was waived by the local ethics committee of the HUG that approves usage of leftover of patient serum collected for diagnostic purposes.
    Consent: Serum samples from unmatched PCR-confirmed COVID-19 hospitalized patients were collected for routine diagnostic purposes under a general informed consent and outpatients were asked if they were willing to return to the hospital after their symptoms had subsided and to donate a serum sample under written general informed consent.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.
    Cell Line Authenticationnot detected.

    Table 2: Resources

    Antibodies
    SentencesResources
    After 3x washing with PBS-T, secondary goat anti-human-IgG antibody conjugated with Alexa488 (Jackson ImmunoResearch, #109-545-088) was diluted 1:200 in PBS and 25μl were applied to each spot.
    anti-human-IgG
    suggested: None
    Experimental Models: Cell Lines
    SentencesResources
    Briefly, Vero B4 cells were transfected with the mammalian expression vector pCG1-SCoV2-S (kindly provided by M. Hoffmann and S. Pöhlmann, DPZ, Göttingen, Germany) using Fugene HD (Promega, #E2311).
    Vero B4
    suggested: CCLV Cat# CCLV-RIE 1146, RRID:CVCL_1912)
    VSV-based pseudo-neutralization assay: VeroE6 cells were seeded in 96-well plates at 2 × 104 cells per well and grown into confluent monolayer overnight.
    VeroE6
    suggested: JCRB Cat# JCRB1819, RRID:CVCL_YQ49)
    Software and Algorithms
    SentencesResources
    GFP positive infected cells were counted with ImageXpress® Micro Widefield High Content Screening System (Molecular Devices) and data analyzed with MetaXpress 5.1.0.41 software.
    MetaXpress
    suggested: (MetaXpress, RRID:SCR_016654)
    Statistical analyses: Analyses were performed with Graph Pad Prism version 8.3.1 software using Fisher’s bilateral exact test and Mann-Whitney U-test where appropriate.
    Graph Pad Prism
    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: We detected the following sentences addressing limitations in the study:
    Our analyses revealed the following limitations of the manufacturer’s seropositivity cut-off. First, with an inter-assay imprecision of 15% assessed at an IgG ratio of 2.09 (above than the 1.5 two cut-off value selected) translating into a LSC of 0.42 IgG ratio, our results indicate that the analytical imprecision is higher than the range of the indeterminate zone proposed by the manufacturer, which encompasses a delta of 0.3 IgG ratio. This implies that any result within the 0.8-1.1 IgG ratio range could be randomly either above, within or below these values just because of analytical imprecision. Secondly, with a LSC of 0.42 our results indicated that a higher IgG ratio cut-off value was needed to secure an optimal specificity and PPV. Adding the 0.42 LSC to the 1.1 cut-off yielded a 1.5 ratio as the IgG seropositivity cut-off with a PPV of 100%, the lower end of the 95%CI still being compatible with a 97% rule-in strategy. Notably, using this cut-off in the subgroup of patients under 21 dpos/dpd, the SP and PPV were still 100%, however, with broader confidence intervals. Similarly, in an attempt to maximize the negative predictive value at the rule-out cut-off, the cut-off had to be decreased from 0.8 to 0.5 IgG ratio in order to reach an overall NPV of 97%, with a 93% at the lower end of the 95CI. In the subgroup of patients under 21 dpos/dpd this interval was found to be substantially larger (95%CI: 45–91). Taken together, these results indicate that at this stage the op...

    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

    SciScore is an automated tool that is designed to assist expert reviewers by finding and presenting formulaic information scattered throughout a paper in a standard, easy to digest format. SciScore checks for the presence and correctness of RRIDs (research resource identifiers), and for rigor criteria such as sex and investigator blinding. For details on the theoretical underpinning of rigor criteria and the tools shown here, including references cited, please follow this link.

  3. Version published to 10.1101/2020.05.02.20080879v1 on medRxiv