Time scale performance of rapid antigen testing for SARS‐CoV‐2: Evaluation of 10 rapid antigen assays

  1. Zakarya Abusrewil
  2. Inas M. Alhudiri
  3. Hamza H. Kaal
  4. Salah Eldin El Meshri
  5. Fawzi O. Ebrahim
  6. Tarek Dalyoum
  7. Abdussamee A. Efrefer
  8. Khaled Ibrahim
  9. Mohammed B. Elfghi
  10. Suleiman Abusrewil
  11. Adam Elzagheid

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Abstract

There is a great demand for more rapid tests for SARS‐CoV‐2 detection to reduce waiting time, boost public health strategies for combating disease, decrease costs, and prevent overwhelming laboratory capacities. This study was conducted to assess the performance of 10 lateral flow device viral antigen immunoassays for the detection of SARS‐CoV‐2 in nasopharyngeal swab specimens. We analyzed 231 nasopharyngeal samples collected from October 2020 to December 2020, from suspected COVID‐19 cases and contacts of positive cases at Biotechnology Research Center laboratories, Tripoli, Libya. The performance of 10 COVID‐19 Antigen (Ag) rapid test devices for the detection of SARS‐CoV‐2 antigen was compared to a quantitative reverse transcription‐polymerase chain reaction (RT‐qPCR). In this study, 161 cases had symptoms consistent with COVID‐19. The mean duration from symptom onset was 6.6 ± 4.3 days. The median cycle threshold ( C t ) of positive samples was 25. Among the 108 positive samples detected by RT‐qPCR, the COVID‐19 antigen (Ag) tests detected 83 cases correctly. All rapid Ag test devices used in this study showed 100% specificity. While tests from six manufacturers had an overall sensitivity range from 75% to 100%, the remaining four tests had a sensitivity of 50%–71.43%. Sensitivity during the first 6 days of symptoms and in samples with high viral loads ( C t  < 25), was 100% in all but two of the test platforms. False‐negative samples had a median C t of 34 and an average duration of onset of symptoms of 11.3 days (range = 5–20 days). Antigen test diagnosis has high sensitivity and specificity in early disease when patients present less than 7 days of symptom onset. Patients are encouraged to test as soon as they get COVID‐19‐related symptoms within 1 week and to seek medical advice within 24 h if they develop disturbed smell/taste. The use of rapid antigen tests is important for controlling the COVID‐19 pandemic and reducing the burden on molecular diagnostic laboratories.

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  1. Version published to 10.1002/jmv.27186
  2. Version published to 10.1101/2021.05.27.21257868v2 on medRxiv
  3. ScreenIT

    SciScore for 10.1101/2021.05.27.21257868: (What is this?)

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

    Table 1: Rigor

    EthicsIRB: Testing was performed at variable times following symptom onset, Ethical approval for this study was granted by Biotechnology Research Center Bioethics committee and informed consent was taken from all participants.
    Consent: Testing was performed at variable times following symptom onset, Ethical approval for this study was granted by Biotechnology Research Center Bioethics committee and informed consent was taken from all participants.
    Sex as a biological variablenot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.

    Table 2: Resources

    Antibodies
    SentencesResources
    Extracted sample was applied on a cassette and allowed to react with a monoclonal anti-SARS-CoV-2 antibody, after a 15-30-min incubation, for the presence or absence of bands and its intensity following antigen-antibody reaction.
    anti-SARS-CoV-2
    suggested: None
    Software and Algorithms
    SentencesResources
    Statistical analysis: Sensitivity, specificity, positive and negative predictive values and accuracy were calculated using MedCalc online statistical software (“MedCalc’s Diagnostic test evaluation calculator,” n.d.).
    MedCalc
    suggested: (MedCalc, RRID:SCR_015044)

    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 study has some limitations. First, the sample size was small for each individual antigen test kit. Second, because the data was collected prospectively based on presence of symptoms or history of contact with infected patient, it was difficult to select patients with different Ct values in enough size. However, if we assumed that the performance of all antigen kits was similar, the data would reliable enough to give credible results. Antigen testing performance is mostly affected by symptoms duration, viral load, manufacturing company, operator experience and qualification. In addition, new SARS-COV-2 variants may alter the performance especially with spike proteins targeted antigen tests (Li et al., 2020; Mahase, 2020). In conclusion, rapid antigen tests have high sensitivity and specificity in early disease when patients present before 7 days of symptom onset. Patients are encouraged to test as soon as they get COVID-19 related symptoms within 1 week and to seek medical advice within 24 hrs. if they develop disturbed smell/taste. The use of rapid antigen tests is important for controlling COVID-19 pandemic and reducing burden on molecular diagnostic laboratories.

    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 10.1101/2021.05.27.21257868v1 on medRxiv