Field evaluation of specificity and sensitivity of a standard SARS-CoV-2 antigen rapid diagnostic test: A prospective study at a teaching hospital in Northern Ghana

  1. Alhassan Abdul-Mumin
  2. Abdulai Abubakari
  3. Faith Agbozo
  4. Abass Abdul-Karim
  5. Benjamin Demah Nuertey
  6. Kareem Mumuni
  7. Anna-Katharina Heuschen
  8. Lisa Hennig
  9. Claudia M. Denkinger
  10. Olaf Müller
  11. Albrecht Jahn

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Abstract

The testing capacity for SARS-CoV-2 in Africa is rather limited. Antigen detection rapid diagnostic tests (Ag-RDTs) are a cheap and rapid alternative to reverse transcriptase-polymerase chain reaction (RT-PCR) tests, but there is little data about their performance under real life conditions in tropical countries. The objective of this study is to evaluate the performance of a standard Ag-RDT in a population of a major hospital in northern Ghana. Prospective, cross-sectional, blinded verification of the performance of the SD Biosensor Standard Q SARS-CoV-2 Ag-RDT under real life conditions in 135 symptomatic patients and 58 contacts of RT-PCR positives at Tamale Teaching Hospital in February 2021. Nasopharyngeal samples were taken under standard conditions and tested against RT-PCR in the hospital laboratory. 193 participants (median age 35 years, 109 male) were included into the study for which both RT-PCR test and Ag-RDT results were available. A total of 42 (22%) were RT-PCR positive. Of the 42 RT-PCR positives, 27 were Ag-RDT positive, resulting in a sensitivity of 64% (95% CI 49–79). Sensitivity among symptomatic patients was 58% (95% CI 38–78). 123 were identified Ag-RDT negatives of the 151 RT-PCR negatives, resulting in a specificity of 81% (95% CI 75–87). SARS-CoV-2 Ag-RDTs appear to have a rather low sensitivity and particularly a low specificity under real life conditions in Africa. The role of existing Ag-RDTs in countries with high-temperature climates and limited resources still needs more data and discussion.

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  1. Version published to 10.1371/journal.pgph.0000040
  2. Version published to 10.1101/2021.06.03.21258300v2 on medRxiv
  3. ScreenIT

    SciScore for 10.1101/2021.06.03.21258300: (What is this?)

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

    Table 1: Rigor

    EthicsConsent: Following verbal informed consent, clinical and demographic data were recorded from the study participants on a standard questionnaire, including specific symptoms, age, and sex.
    IACUC: Ethical aspects: The evaluation protocol was approved by the Ethical Review Committee of the Tamale Teaching Hospital.
    Sex as a biological variablenot detected.
    Randomizationnot detected.
    BlindingStudy design and participants: This study was a cross-sectional, blinded verification study of the performance of the Standard Q SARS-CoV-2 Ag-RDT under real life conditions in the Tamale Teaching Hospital.
    Power AnalysisThe sample size of 200 was determined using the Cochrane (1977) formulae for sample size calculation.

    Table 2: Resources

    Software and Algorithms
    SentencesResources
    The sample size of 200 was determined using the Cochrane (1977) formulae for sample size calculation.
    Cochrane
    suggested: (Cochrane Library, RRID:SCR_013000)
    The RT-PCR referral laboratory standard assay used in the Public Health Reference Laboratory was the Agilent AriaMx real-time PCR analyser.
    Agilent AriaMx
    suggested: (Agilent AriaMx Real-time PCR System, RRID:SCR_019469)

    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:
    The limitations of this study are firstly that it was done in one center of one country only, thus limiting generalizability. Secondly, the overall sample size was small and further subgroup analyses to better understand the data were not possible. Thirdly, the temperature at time of testing was not recorded thus limiting a differentiated understanding of the impact of temperature. And while a limitation, as not performed in manufacturer recommended temperature range, the strength of this study is, that it has been done under real life conditions in a high-temperature, limited resource country.

    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 10.1101/2021.06.03.21258300v1 on medRxiv