Excellent negative predictive value (99.8%) of two rapid molecular COVID-19 tests compared to conventional RT-PCR for SARS-CoV-2 (COVID-19) in 2,011 tests performed in a single centre

  1. KW Leong
  2. TL Law
  3. AS Saiful
  4. Kang
  5. Woo
  6. Chow
  7. ZL Yong

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Abstract

Conventional Reverse Transcription Polymerase Chain Reaction (RT-PCR) remains the gold standard for testing SARS-CoV-2. Since their availability, two rapid molecular COVID-19 tests were performed in parallel with RT-PCR in all urgent and emergency admissions, as the negative predictive value was not yet ascertained. In this study, we present the data of 2,011 test results using either ID Now COVID-19 (Abbott) (Abbott ID NOW) or Xpert Xpress SARS-CoV-2 (Cepheid) (GeneXpert) tests comparing to conventional RT-PCR results. The negative predictive value is 99.8%(3 false negatives out of 1,964 tests) using a cut-off CT value of 40. Using a cut-off of RT-PCR CT value of 30 (predicting infectivity), the negative predictive value is reduced to 99.9% (1 out of 1,964 tests). With these results, we feel confident to recommend the immediate use of the rapid PCR tests alone and to use conventional RT-PCR for confirmation testing after.

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    SciScore for 10.1101/2021.06.20.21258392: (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.
    Randomizationnot detected.
    Blindingnot detected.
    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: 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.

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  2. Version published to 10.1101/2021.06.20.21258392v1 on medRxiv