Clinical assessment of SARS-CoV-2 antigen rapid detection compared with RT-PCR assay for emerging variants at a high-throughput community testing site in Taiwan

Abstract

Objectives: With the emergence of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) B.1.1.7 lineage in the ongoing coronavirus disease 2019 (COVID-19) pandemic, Taiwan confronted a COVID-19 flare up in May 2021. Large-scale, accurate, affordable and rapid diagnostic tests such as the lateral flow assay can help to prevent community transmission, but their performance characteristics in real-world conditions and relevant subpopulations remain unclear.

Methods: The COVID-19 Antigen Rapid Test Kit (Eternal Materials, New Taipei City, Taiwan) was used in a high-throughput community testing site; the paired reverse transcription polymerase chain reaction (RT-PCR) results served as a reference for sensitivity and specificity calculations.

Results: Of 2096 specimens tested using the rapid antigen test, 70 (3.33%) were positive and 2026 (96.7%) were negative. This clinical performance was compared with the RT-PCR results. The sensitivity and specificity of the rapid antigen test were 76.39% [95% confidence interval (CI) 64.91-85.60%] and 99.26% (95% CI 98.78-99.58%), respectively, with high sensitivity in subjects with cycle threshold values ≤24. Further, the rapid antigen test detected the SARS-CoV-2 B.1.1.7 lineage effectively.

Conclusions: Considering the short turnaround times and lower costs, this simple SARS-CoV-2 antigen detection test for rapid screening combined with RT-PCR as a double confirmatory screening tool can facilitate the prevention of community transmission during COVID-19 emergencies.

Keywords: B.1.1.7 lineage; COVID-19; Community transmission; Rapid antigen test; Reverse transcription polymerase chain reaction; SARS-CoV-2.

Figure 1

Flowchart of the study using the rapid antigen test (ART) as a screening tool in combination with reverse transcription polymerase chain reaction (RT-PCR) for severe acute respiratory syndrome coronavirus-2 infection in densely populated areas. CECC, Central Epidemic Command Centre in Taiwan.

Figure 2

Discordant analysis between coronavirus disease 2019 rapid antigen test and reverse transcription polymerase chain reaction (RT-PCR). Ct, cycle threshold.