Development and Evaluation of a new Swiss Made SARS-CoV-2 antigen-detecting rapid test

  1. Ducrest P.J.

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Abstract

There is an urgent need in rapid diagnostic test (RDT) to detect antigen of SARS-CoV-2 to reduce the spread of COVID-19 outbreak. We have developed a rapid and simple point-of-care lateral flow immunoassay (LFIA) detecting nucleocapsid antigen of SARS-CoV-2 in 10 minutes. The aim of this study is to evaluate the diagnostic performance and analytical sensitivity of this RDT. RT-PCR positive nasopharyngeal swab samples (n=20) for SARS-CoV-2 and 40 negative control samples were studied. Analytical sensitivity was assessed using Gamma-irradiated SARS-CoV-2 and the limit of detection (LOD) was determined at 1.4 × 10 2 TCID 50 /ml. Overall, RDT diagnostic sensitivity was 90% (95% confidence interval [95%CI]: 67-98%) and specificity 98% (95% CI: 85-100%). The sensitivity was 100% (95% CI: 75-100%) when using only samples with a RT-PCR Cycle threshold lower than 30. This antigen RDT displays a high diagnostic accuracy for SARS-CoV-2 antigen detection in high COVID-19 prevalence settings. Its use could be considered in the absence of routine RT-PCR facilities such in low-income countries.

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  1. ScreenIT

    SciScore for 10.1101/2021.03.25.21252280: (What is this?)

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

    Table 1: Rigor

    Institutional Review Board Statementnot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.

    Table 2: Resources

    Antibodies
    SentencesResources
    The gold nanoparticles (Nanocomposix, San Diego, USA) are coated with rabbit anti-Nucleocapsid antibodies.
    anti-Nucleocapsid
    suggested: None
    The control line (C) is composed of a goat anti-rabbit antibody (Jackson ImmunoResearch Europe, Ely, UK).
    anti-rabbit
    suggested: None
    When a positive sample flows through the test membrane, the anti-SARS-CoV-2 antibodies present on the membrane (Test line) capture the antigen and form a colored conjugate complex on the test line.
    anti-SARS-CoV-2
    suggested: None

    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:
    There are several limitations to this study. First, we present here the results of a method evaluation study and not a seroprevalence study. Therefore, the PPV obtained here (based on a 33.3% proportion of cases defined as laboratory confirmed SARS-CoV-2 by RT-PCR) will probably be lower in a low prevalence setting. Another limitation of this validation study lies in its limited sample size leading to broad 95% confidence intervals, requiring confirmation of these data at a larger scale. Finally, our present conclusions only apply to this RDT, and must not be applied to any other RDTs currently available. In conclusion, this RDT is not meant to replace a SARS-CoV-2 RT-PCR but could be a reliable option for quickly assessing the presence of SARS-CoV-2 antigen in moderate to high COVID-19 prevalence settings and when high viral loads are expected, especially in situations where a rapid result is needed or where RT-PCR is not available. Further investigations in low prevalence situations and using capillary blood are necessary.

    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.

  2. Version published to 10.1101/2021.03.25.21252280 on medRxiv