The Effect of Pooling on the Detection of the Nucleocapsid Protein of SARS-CoV-2 with Rapid Antigen Tests

  1. Tim Berking
  2. Sabrina Lorenz
  3. Alexander Ulrich
  4. Joachim Greiner
  5. Eric Kervio
  6. Jennifer Bremer
  7. Christina Wege
  8. Tatjana Kleinow
  9. Clemens Richert

Reviewed by

Read the full article See related articles

Discuss this preprint

Start a discussion What are Sciety discussions?

Listed in

Log in to save this article

Abstract

The COVID-19 pandemic puts significant stress on the viral testing capabilities of many countries. Rapid point-of-care (PoC) antigen tests are valuable tools but implementing frequent large scale testing is costly. We have developed an inexpensive device for pooling swabs, extracting specimens, and detecting viral antigens with a commercial lateral flow test for the nucleocapsid protein of SARS-CoV-2 as antigen. The holder of the device can be produced locally through 3D printing. The extraction and the elution can be performed with the entire set-up encapsulated in a transparent bag, minimizing the risk of infection for the operator. With 0.35 mL extraction buffer and six swabs, including a positive control swab, 43 ± 6% (n = 8) of the signal for an individual extraction of a positive control standard was obtained. Image analysis still showed a signal-to-noise ratio of approximately 2:1 at 32-fold dilution of the extract from a single positive control swab. The relative signal from the test line versus the control line was found to scale linearly upon dilution (R2 = 0.98), indicating that other pooling regimes are conceivable. A pilot project involving 14 participants and 18 pooled tests in a laboratory course at our university did not give any false positives, and an individual case study confirmed the ability to detect a SARS-CoV-2 infection with five-fold or six-fold pooling, including one swab from a PCR-confirmed COVID patient. These findings suggest that pooling can make frequent testing more affordable for schools, universities, and similar institutions, without decreasing sensitivity to an unacceptable level.

Article activity feed

  1. Version published to 10.3390/diagnostics11071290
  2. ScreenIT

    SciScore for 10.1101/2021.03.11.21252969: (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

    Software and Algorithms
    SentencesResources
    Positive control swabs provided with the Abbott kits were used as source of SARS-CoV-2 antigen.
    Abbott
    suggested: (Abbott, RRID:SCR_010477)
    F) cellular phone and image analysis was performed using the free program ImageJ (NIH).
    ImageJ
    suggested: (ImageJ, RRID:SCR_003070)

    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

    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 10.1101/2021.03.11.21252969 on medRxiv