Rapid antigen test as a screening tool for SARS-CoV-2 infection: Head-to-head comparison with qRT-PCR in Ethiopia

Dabesa Gobena; Esayas Kebede Gudina; Getu Gebre; Tizta Tilahun Degfie; Zeleke Mekonnen

doi:10.1016/j.heliyon.2023.e23518

Rapid antigen test as a screening tool for SARS-CoV-2 infection: Head-to-head comparison with qRT-PCR in Ethiopia

Heliyon. 2023 Dec 9;10(1):e23518. doi: 10.1016/j.heliyon.2023.e23518. eCollection 2024 Jan 15.

Authors

Dabesa Gobena^{1

2}, Esayas Kebede Gudina³, Getu Gebre¹, Tizta Tilahun Degfie^{4

5}, Zeleke Mekonnen²

Affiliations

¹ Public Health Emergency Management and Health Research Directorate, Oromia Health Bureau, Addis Ababa, Ethiopia.
² School of Medical Laboratory Sciences, Institute of Health, Jimma University, Jimma, Ethiopia.
³ Department of Internal Medicine, Jimma University, Jimma, Ethiopia.
⁴ Department of Reproductive Health and Population Studies, College of Medicine and Health Sciences, Bahir Dar University, Bahir Dar, Ethiopia.
⁵ Fenot Project, Department of Global Health and Population, Harvard T.H. Chan School, Ethiopia.

Abstract

Objective: This study aimed to determine the diagnostic accuracy of the antigen rapid diagnostic test (Ag-RDT) as a screening tool for SARS-CoV-2 infection compared to Quantitative reverse transcription polymerase chain reaction (qRT-PCR).

Methods: This study was conducted at six referral hospitals in Oromia Region, Ethiopia. One thousand seven hundred twenty-one patients who visited the hospitals for various medical conditions were tested with qRT-PCR and/or Ag-RDTs. Qualitative detection of SARS-CoV-2 antigen was performed using the Panbio™ COVID-19 Ag rapid test device.

Results: Compared with qRT-PCR, Ag-RDTs had a sensitivity of 33.3 % (95%CI: 30.9%-35.9 %) and a specificity of 99.3 % (95%CI: 98.8%-99.7 %) to detect active SARS-CoV-2 infection. The area under the receiver operator curve was 0.67 (95%CI: 0.63-0.69). The sensitivity of Ag-RDTs appeared high in patients with shortness of breath (73.3 %) and those presenting with all three symptoms - fever, cough, and dyspnea (71.4 %). In all instances, specificity was more than 98 %. The Ag-RDT positivity rate also correlated well with viral load: 51.7 % in cases with cycle threshold (Ct) < 25 (high viral load) and only 3.4 % when Ct > 25 (low viral load).

Conclusion: Although Ag-RDT for diagnosing SARS-CoV-2 is a good option as a point-of-care screening tool, it has a low sensitivity to detect active infections. Using Panbio™ COVID-19 Ag Rapid test for diagnostic and treatment decisions may lead to a false negative, resulting in patient misdiagnosis, ultimately contributing to disease spread and poor patient outcome.

Keywords: Ag-RDT; COVID-19; Comparison; Ethiopia; Panbio; qRT-PCR.