Limit of detection in different matrices of 19 commercially available rapid antigen tests for the detection of SARS-CoV-2

  1. Ana I. Cubas-Atienzar
  2. Konstantina Kontogianni
  3. Thomas Edwards
  4. Dominic Wooding
  5. Kate Buist
  6. Caitlin R. Thompson
  7. Christopher T. Williams
  8. Edward I. Patterson
  9. Grant L. Hughes
  10. Lisa Baldwin
  11. Camille Escadafal
  12. Jilian A. Sacks
  13. Emily R. Adams

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Abstract

In the context of the coronavirus disease 2019 (COVID-19) pandemic there has been an increase of the use of antigen-detection rapid diagnostic tests (Ag-RDT). The performance of Ag-RDT vary greatly between manufacturers and evaluating their analytical limit of detection (LOD) has become high priority. Here we describe a manufacturer-independent evaluation of the LOD of 19 marketed Ag-RDT using live SARS-CoV-2 spiked in different matrices: direct culture supernatant, a dry swab, and a swab in Amies. Additionally, the LOD using dry swab was investigated after 7 days’ storage at − 80 °C of the SARS-CoV-2 serial dilutions. An LOD of ≈ 5.0 × 10 2  pfu/ml (1.0 × 10 6  genome copies/ml) in culture media is defined as acceptable by the World Health Organization. Fourteen of 19 Ag-RDTs (ActiveXpress, Espline, Excalibur, Innova, Joysbio, Mologic, NowCheck, Orient, PanBio, RespiStrip, Roche, Standard-F, Standard-Q and Sure-Status) exceeded this performance criteria using direct culture supernatant applied to the Ag-RDT. Six Ag-RDT were not compatible with Amies media and a decreased sensitivity of 2 to 20-fold was observed for eleven tests on the stored dilutions at − 80 °C for 7 days. Here, we provide analytical sensitivity data to guide appropriate test and sample type selection for use and for future Ag-RDT evaluations.

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  1. Version published to 10.1038/s41598-021-97489-9
  2. ScreenIT

    SciScore for 10.1101/2021.03.19.21253950: (What is this?)

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

    Table 1: Rigor

    Institutional Review Board Statementnot detected.
    Randomizationnot detected.
    BlindingResults were interpreted by two operators, each blinded to the result of the other.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.
    Cell Line Authenticationnot detected.

    Table 2: Resources

    Experimental Models: Cell Lines
    SentencesResources
    SARS-CoV-2 serial dilutions and quantification of copy numbers: The SARS-CoV-2 isolate REMRQ0001/Human/2020/Liverpool was propagated in Vero E6 cells (C1008; African green monkey kidney cells), maintained in DMEM with 2% fetal bovine serum (FBS) and 0.05 mg/ml gentamycin.
    Vero E6
    suggested: RRID:CVCL_XD71)
    Software and Algorithms
    SentencesResources
    .), referred to as Espline, (5) Genedia W COVID-19 Ag (Green Cross Medical Science), referred to as Genedia, (6) iChroma COVID-19 Ag Test (Boditech Medical Inc.), referred to as iChroma, (7) Innova SARS-CoV-2 Antigen Rapid (Innova Medical Group Ltd.), referred to as Innova, (8) Mologic COVID-19 Ag Test device (Mologic Ltd), referred to as Mologic, (9) NowCheck COVID-19 Ag test (Bionote Inc.), referred to as NowCheck, (10) Panbio™ COVID-19 Ag Rapid Test (Abbott Rapid Diagnostics), referred to as Panbio, (11) Rapid SARS-CoV-2 Antigen test card (Excalibur Healthcare Services), referred to as Excalibur, (12
    Excalibur Healthcare
    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:
    This analytical study has some limitations, as only a single isolate (REMRQ0001/Human/2020/Liverpool) was used to assess the LODs but our results are consistent with other recently-published analyses30,31. To the authors knowledge, all 19 tests evaluated here detect the nucleoprotein, presumably chosen for abundance and relative low mutation rate and therefore hypothesized to pick up all currently known variants32,33. Another limitation is that only one lot per kit was evaluated. There is a growing number of studies suggesting that although antigen detection is less analytically sensitive than nucleic acid amplification techniques, it may strongly correlate with culturable virus, which may be a proxy for transmissibility. Hence Ag-RDTs could be informative for test, trace, isolate processes for the most infectious individuals10–15. Viral loads have been estimated to range from 108 to 1011 gcn/ml in the most infectious patients34–36. The majority of Ag-RDTs evaluated here have an LOD predicted to successfully diagnose infected individuals with higher viral loads in this range across all matrices, except Joysbio that had an LOD of 5.4 × 108 gcn/ml in dry swab. Further, Biocredit, iChroma, Standard-F and Genedia tests had LOD greater than 1.0 × 108 gcn/ml when using swabs placed in Amies and In conclusion, the most sensitive tests with an LOD ≤ 5.0 × 102 pfu/ml (≈ 1.2 ×106 gcn/ml) on dry swabs and direct culture supernatant were Espline, Mologic, Sure-Status and Roche and the le...

    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 10.1101/2021.03.19.21253950 on medRxiv