Performance of three rapid antigen tests against the SARS-CoV-2 Omicron variant

  1. Sanjat Kanjilal
  2. Sujata Chalise
  3. Adnan Shami Shah
  4. Chi-An Cheng
  5. Yasmeen Senussi
  6. Rockib Uddin
  7. Vamsi Thiriveedhi
  8. Ha Eun Cho
  9. Seamus Carroll
  10. Jacob Lemieux
  11. Sarah Turbett
  12. David R Walt

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Abstract

Rapid antigen detection tests (RADTs) for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are now in widespread use in the United States. RADTs play an important role in maintaining an open society but require periodic reassessment to ensure test performance remains intact as the virus evolves. The nucleocapsid (N) protein is the target for the majority of RADTs and the SARS-CoV-2 Omicron variant has several N protein mutations that are previously uncharacterized. We sought to assess the impact of these mutations by testing 30 Omicron variant samples across a wide range of viral loads on three widely used RADTs: the iHealth COVID-19 Antigen Rapid Test, the ACON Laboratories FlowFlex COVID-19 Antigen Home Test, and the Abbott BinaxNOW COVID-19 Antigen Card, using 30 Delta variant samples as a comparator. We found no change in the analytic sensitivity of all three RADTs for detection of Omicron versus Delta, but noted differences in performance between assays. No RADT was able to detect samples with a cycle threshold (Ct) value of ≥27.5 for the envelope gene target on the Roche cobas RT-PCR assay. Epidemiologic studies are necessary to correlate these findings with their real-world performance.

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  1. ScreenIT

    SciScore for 10.1101/2022.02.17.22271142: (What is this?)

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

    Table 1: Rigor

    EthicsIRB: This study was deemed non-human subjects research and approved by the Mass General Brigham Institutional Review Board (protocol 2021P003604).
    Sex as a biological variablenot detected.
    Randomizationnot detected.
    BlindingAssays were run in duplicate for each RADT and results were evaluated after a 15 minute incubation period by two independent readers blinded to the variant status and Ct value of the sample.
    Power Analysisnot detected.

    Table 2: Resources

    No key resources detected.

    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:
    The major limitation of our study is the sample size, which limits drawing statistically significant conclusions regarding small differences in test performance. A larger study is warranted to further investigate the differences seen between our RADTs, as even small differences can have a large impact when scaled to the population level. Another limitation is our use of frozen samples in universal transport media rather than direct testing from a patient, but we would not expect there to be a major impact from one to two freeze-thaws on assay performance and the volume of analyte used in each assay was optimized in an earlier study for mimicking real-world performance12. A major strength of this study was the ability to compare three different RADTs using identical clinical samples, which allows for a robust comparison of performance. In summary, the analytic sensitivity versus Omicron remains stable in our head-to-head comparison of three of the most common RADTs in use in the United States. However, there were differences in inter-assay performance that warrant further study. Our findings will provide a degree of assurance that at-home testing should perform as expected compared to prior waves and also sets a baseline for comparison with future SARS-CoV-2 variants.

    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.

    Results from scite Reference Check: We found no unreliable references.

    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 10.1101/2022.02.17.22271142v1 on medRxiv