Investigating sensitivity of nasal or throat (ISNOT): A combination of both swabs increases sensitivity of SARS-CoV-2 rapid antigen tests

  1. Barbara L Goodall
  2. Jason J LeBlanc
  3. Todd F Hatchette
  4. Lisa Barrett
  5. Glenn Patriquin

Reviewed by

Read the full article See related articles

Listed in

Log in to save this article

Abstract

The COVID-19 pandemic has been hallmarked by several waves of variants of concern (VoCs), each with novel challenges. Currently, the highly transmissible Omicron VOC is predominant worldwide, and sore throat is common among other cold-like symptoms. Anecdotes on social media suggested sampling one’s throat can increase sensitivity for Omicron detection by antigen-based rapid testing devices (Ag-RDTs). This work determines whether the sensitivity of Ag-RDTs designed for nasal sampling is altered with use of self-administered throat swabs in self-perceived asymptomatic individuals. This investigation compared results of a common Ag-RDT (i.e. Abbott Panbio COVID-19 Ag Rapid Test Device) using three sampling sites: nasal swab; throat swab and; combined nasal/throat. All Ag-RDT results were confirmed with molecular testing. Compared to RT-PCR, samples from nasal or throat swabs each detected 64.5% of SARS-CoV-2 cases; however, combining the contributions of each swab increased sensitivity to 88.7%. This trend was also evident with the Rapid Response Ag-RDT (BTNX), which uses a more flexible swabs than Panbio. When nasal swab collection was compared to paired sampling of the nasal/throat using a single swab with the Panbio Ag-RDT, the sensitivity of each was 68.4% and 81.6%, respectively. No false-positive results were observed with nasal, throat, or combined nasal/throat sampling. Self-administered throat and nasal/throat swabs both had >90% acceptability. These findings support the use of self-collected combined nasal/throat sampling for Ag-RDT based SARS-CoV-2 detection in self perceived asymptomatic individuals.

Article activity feed

  3. ScreenIT

    SciScore for 10.1101/2022.01.18.22269426: (What is this?)

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

    Table 1: Rigor

    EthicsConsent: After providing verbal consent, participants were verbally instructed on, and observed performing, a self-collected bilateral nasal swab, and then guided on self-collection of a posterior oropharyngeal swab, with the aid of an anatomical diagram of the mouth.
    Sex as a biological variablenot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.

    Table 2: Resources

    Software and Algorithms
    SentencesResources
    Descriptive statistics were used to report participation and testing outcomes, using MedCalc (http://www.medcalc.org) where appropriate.
    MedCalc
    suggested: (MedCalc, RRID:SCR_015044)

    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:
    This investigation is not without limitations. Our adult population is from a single centre during a seven-day period, at a community testing centre. There was no collection of clinical information related to patient demographics, timing from exposure, immunization history, or recent consumption of food or drink. One of the criteria for attending the testing site was self-described asymptomatic status. However, mild symptoms may not have been recognized as Omicron infection. Practically speaking, swabbing both nasal and throat using a single swab can be done without regard for timing of symptoms or exposure, and should increase rates of detection using Ag-RDTs. This is particularly important as self-directed testing and management become a tool of endemic living, these data add confidence to the ability of individuals to adequately perform reliable sample collection in a real-world setting. Although this project focused on the Abbott Panbio Ag-RDT, the concordant results obtained using the BTNX Rapid Response suggest that this enhanced detection rate using a combined swab is applicable to other lateral flow tests, although further studies are warranted. While molecular confirmation with RT-PCR was available, RTB is not a typical testing matrix. Despite our previous validations of RTB for this application16, this approach is not as sensitive as an independent collection of swabs for RT-PCR testing using dedicated transport media. As such, the sensitivity of Ag-RDTs may be over...

    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.

  4. Version published to 10.1101/2022.01.18.22269426v1 on medRxiv