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. 2021 Jul:37:100954.
doi: 10.1016/j.eclinm.2021.100954. Epub 2021 Jun 9.

Validation of a rapid antigen test as a screening tool for SARS-CoV-2 infection in asymptomatic populations. Sensitivity, specificity and predictive values

Alejandro Fernandez-Montero  1   2 , Josepmaria Argemi  2   3 , José Antonio Rodríguez  2   4   5 , Arturo H Ariño  6 , Laura Moreno-Galarraga  2   7   8
Affiliations

Validation of a rapid antigen test as a screening tool for SARS-CoV-2 infection in asymptomatic populations. Sensitivity, specificity and predictive values

Alejandro Fernandez-Montero et al. EClinicalMedicine. 2021 Jul.

Abstract

Background: Early diagnosis of SARS-CoV-2 infection is essential to reduce disease spread. Rapid antigen tests have not been sufficiently evaluated in asymptomatic patients to be used as massive population screening tools.

Methods: Head-to-head evaluation of Roche SARS-CoV-2 Rapid Antigen Test and real-time reverse transcription polymerase chain reaction (RT-PCR) as SARS-CoV-2 screening tools performed in asymptomatic adults from a semi-closed community in University of Navarra (Spain) from November 2020 to January 2021. Sensitivity, specificity and predictive values were calculated using RT-PCR as reference method.

Findings: Roche SARS-CoV-2 Rapid Antigen Test was performed on 2542 asymptomatic adults in a community with a SARS-CoV-2 incidence of 1·93%. It showed a sensitivity of 71·43% (CI 95%: 56·74 - 83·42) and a specificity of 99·68% (CI 95%: 99·37 - 99·86). Positive Predictive Value was 81·4 (CI 95% 66·6 - 91·61) and Negative Predictive Value was 99·44 (CI 95% 99·06 - 99·69). Test sensitivity was related to viral load, with higher sensitivity in RT-PCR cycle threshold (Ct) values under 25 (93·75%, CI 95%: 71·96 - 98·93), that dropped to 29·41% (CI 95%: 10·31- 55·96) in RT-PCR Ct values above 25.

Interpretation: This study suggests that rapid antigen tests are less effective in asymptomatic population, when compared with RT-PCR. Further studies are needed to evaluate different options to improve screenings based on rapid antigen test, such as the use of clinical questionnaires to select higher risk-participants, the confirmation of negative results with RT-PCR or the use of repetitive sequential testing.

Funding: This research received no external funding.

Keywords: COVID-19; RT-PCR; Rapid antigen detection; SARS-CoV-2; Screening tool.

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Conflict of interest statement

The authors have no conflict of interest to disclose. Roche Diagnostics International Ltd. provided the rapid antigen tests required for the study. A contract was signed with Roche Diagnostics International Ltd. with the following clauses on dataset and publication: "any Study data generated by the Universidad de Navarra shall be owned by the Institution. Roche had access to study results, but not to study data. After the first submission for publication, Roche may use the Final Study Report for any and all purposes, including but not limited to, research and development, marketing, or future regulatory submissions. A manuscript for publication shall be submitted to Roche for review not later than 180 (one hundred and eighty) days after completion of the Study. Any publications shall comply with applicable laws and guidelines and the recommendations of the International Committee of Medical Journal Editors. Roche will have no role on the decision to submit the paper for publication. The Universidad de Navarra shall safeguard intellectual property rights and provide to Roche the manuscript in its near final form at least 3 months prior to submission to obtain Roche´s scientific check as well as to coordinate with Roche the date of publication in order to preclude any preliminary publication which may be detrimental to the novelty of any proposed patent application. Roche´s support of the Study shall be disclosed in any Publication, as required by applicable laws, regulations, codes, and guidelines."

Figures

Fig. 1
Fig. 1
Study Flow-chart: Validation of a rapid antigen test as a screening tool for SARS-CoV-2 infection in asymptomatic populations. * Fever, persistent cough, or shortness of breath.
Fig. 2
Fig. 2
Graphical representation of positive and negative antigen results according to RT-PCR Ct values. Validation study of a rapid antigen test as a screening tool for SARS-CoV-2 infection. RT-PCR: Real-time reverse transcription polymerase chain reaction; Ct: cycle threshold.
See this image and copyright information in PMC

Comment in

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