Rapid comparative evaluation of SARS-CoV-2 rapid point-of-care antigen tests

  1. Anna Denzler
  2. Max L. Jacobs
  3. Victoria Witte
  4. Paul Schnitzler
  5. Claudia M. Denkinger
  6. Michael Knop

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Abstract

Purpose

The objective of this study was to develop a scalable approach for direct comparison of the analytical sensitivities of commercially available SARS-CoV-2 antigen point-of-care tests (AgPOCTs) to rapidly identify poor-performing products.

Methods

We present a methodology for quick assessment of the sensitivity of SARS-CoV-2 AgPOCTs suitable for quality evaluation of many different products. We established reference samples with high, medium, and low SARS-CoV-2 viral loads along with a SARS-CoV-2 negative control sample. Test samples were used to semi-quantitatively assess the analytical sensitivities of 32 different commercial AgPOCTs in a head-to-head comparison.

Results

Among 32 SARS-CoV-2 AgPOCTs tested, we observe sensitivity differences across a broad range of viral loads (9.8 × 10 8 to 1.8 × 10 5 SARS-CoV-2 genome copies per ml). 23 AgPOCTs detected the Ct25 test sample (1.6 × 10 6 copies/ml), while only five tests detected the Ct28 test sample (1.8 × 10 5 copies/ml). In the low-range of analytical sensitivity, we found three saliva spit tests only delivering positive results for the Ct21 sample (2.7 × 10 7 copies/ml). Comparison with published data supports our AgPOCT ranking. Importantly, we identified an AgPOCT widely offered, which did not reliably recognize the sample with the highest viral load (Ct16 test sample with 9.8 × 10 8 copies/ml) leading to serious doubts about its usefulness in SARS-CoV-2 diagnostics.

Conclusion

The results show that the rapid sensitivity assessment procedure presented here provides useful estimations on the analytical sensitivities of 32 AgPOCTs and identified a widely-spread AgPOCT with concerningly low sensitivity.

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  1. Version published to 10.1007/s15010-022-01810-1
  2. Version published to 10.1101/2021.07.29.21261314v2 on medRxiv
  3. ScreenIT

    SciScore for 10.1101/2021.07.29.21261314: (What is this?)

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

    Table 1: Rigor

    Ethicsnot detected.
    Sex as a biological variablenot detected.
    RandomizationFor qualitative evaluation of the visibility of the test bands (positive versus negative score), RGB pictures of AgPOCT results from randomly chosen replicates were evaluated independently by three individuals in a blinded manner.
    BlindingFor qualitative evaluation of the visibility of the test bands (positive versus negative score), RGB pictures of AgPOCT results from randomly chosen replicates were evaluated independently by three individuals in a blinded manner.
    Power Analysisnot detected.

    Table 2: Resources

    Software and Algorithms
    SentencesResources
    Test results were quantified by measuring the background corrected signal intensities of the test (T) band versus control (C) band in ImageJ (v1.53c) using the “Gels” analysis function usually used for quantification of Western Blot bands.
    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.

    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 10.1101/2021.07.29.21261314v1 on medRxiv