Acceptability, Usability, and Performance of Lateral Flow Immunoassay Tests for Severe Acute Respiratory Syndrome Coronavirus 2 Antibodies: REACT-2 Study of Self-Testing in Nonhealthcare Key Workers

  1. Bethan Davies
  2. Marzieh Araghi
  3. Maya Moshe
  4. He Gao
  5. Kimberly Bennet
  6. Jordan Jenkins
  7. Christina Atchison
  8. Ara Darzi
  9. Deborah Ashby
  10. Steven Riley
  11. Wendy Barclay
  12. Paul Elliott
  13. Helen Ward
  14. Graham Cooke

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Abstract

Background

Seroprevalence studies are essential to understand the epidemiology of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Various technologies, including laboratory assays and point-of-care self-tests, are available for antibody testing. The interpretation of seroprevalence studies requires comparative data on the performance of antibody tests.

Methods

In June 2020, current and former members of the United Kingdom police forces and fire service performed a self-test lateral flow immunoassay (LFIA), had a nurse-performed LFIA, and provided a venous blood sample for enzyme-linked immunosorbent assay (ELISA). We present the prevalence of antibodies to SARS-CoV-2 and the acceptability and usability of self-test LFIAs, and we determine the sensitivity and specificity of LFIAs compared with laboratory ELISA.

Results

In this cohort of 5189 current and former members of the police service and 263 members of the fire service, 7.4% (396 of 5348; 95% confidence interval [CI], 6.7–8.1) were antibody positive. Seroprevalence was 8.9% (95% CI, 6.9–11.4) in those under 40 years, 11.5% (95% CI, 8.8–15.0) in those of nonwhite ethnicity, and 7.8% (95% CI, 7.1–8.7) in those currently working. Self-test LFIA had an acceptability of 97.7% and a usability of 90.0%. There was substantial agreement between within-participant LFIA results (kappa 0.80; 95% CI, 0.77–0.83). The LFIAs had a similar performance: compared with ELISA, sensitivity was 82.1% (95% CI, 77.7–86.0) self-test and 76.4% (95% CI, 71.9–80.5) nurse-performed with specificity of 97.8% (95% CI, 97.3–98.2) and 98.5% (95% CI, 98.1–98.8), respectively.

Conclusions

A greater proportion of this nonhealthcare key worker cohort showed evidence of previous infection with SARS-CoV-2 than the general population at 6.0% (95% CI, 5.8–6.1) after the first wave in England. The high acceptability and usability reported by participants and similar performance of self-test and nurse-performed LFIAs indicate that the self-test LFIA is fit for purpose for home testing in occupational and community prevalence studies.

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  1. Version published to 10.1093/ofid/ofab496
  2. ScreenIT

    SciScore for 10.1101/2021.06.21.21259254: (What is this?)

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

    Table 1: Rigor

    EthicsConsent: Consent was obtained from participants who had been symptom-free for the previous 7-days and they were provided with instructions, a set of study ID stickers (barcode), a self-test LFIA kit, a nasopharyngeal kit and a saliva kit.
    IRB: Ethical approvals: This work was undertaken as part of the REACT-2 study, with ethical approval from South Central–Berkshire B Research Ethics Committee (REC ref: 20/SC/0206; IRAS 283805).
    Sex as a biological variablenot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.

    Table 2: Resources

    Antibodies
    SentencesResources
    Participants had a venous blood sample analysed by ELISA (Abbott, USA) for SARS-CoV-2 IgG antibody.
    SARS-CoV-2 IgG
    suggested: None
    Software and Algorithms
    SentencesResources
    Participants had a venous blood sample analysed by ELISA (Abbott, USA) for SARS-CoV-2 IgG antibody.
    Abbott
    suggested: (Abbott, RRID:SCR_010477)
    Analyses were conducted in STATA version 13.1 or higher (StataCorp, College Station, TX, USA).
    STATA
    suggested: (Stata, RRID:SCR_012763)
    StataCorp
    suggested: (Stata, RRID:SCR_012763)

    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:
    Strengths and limitations: We aimed to replicate the experience of completing a home self-test LFIA as a means of obtaining prevalence of previous SARS-CoV-2 infection in non-healthcare occupational settings by providing participants with no additional assistance, beyond the test instruction materials. The idea was that, if successful, this could then be extended to obtain prevalence estimates in the wider population at low cost, without the need for supervision by a healthcare practitioner. We found little difference between the results of LFIAs administered as a self-test or by a nurse, supporting the unsupervised use of the LFIA. However, our results might not be fully generalisable. The majority of participants were recruited from the Airwave occupational cohort [9]. The cohort is not demographically (age, sex, ethnicity, geography) representative of the adult population of England, participants had to be able to travel to a test site (mostly in a private vehicle) and, being an occupational cohort, participants were healthier than the general population (‘healthy cohort’ effect [9]). Participants (emergency service staff) may also have been more familiar with medical procedures, which may have had an impact on the generalisability of the usability and acceptability findings to the general population. Nonetheless, parallel studies carried out in the community at around the same time provided similar results on usability and acceptability (although estimates of prevalence w...

    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.
    • Thank you for including a protocol registration statement.

    Results from scite Reference Check: We found no unreliable references.

    About SciScore

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  3. Version published to 10.1101/2021.06.21.21259254v2 on medRxiv
  4. Version published to 10.1101/2021.06.21.21259254v1 on medRxiv