The study of sensitivity, specificity and accuracy of Antigen Test Kits (ATK) compare with Real time RT-PCR for Coronavirus 2019 at Coronavirus 2019's field screening service, Bangkok

Abstract

Introduction: Currently, COVID-19 is still spreading in several communities and organizations. Active case finding is an important method to indicate infected cases and deliver them to treat for stopping the transmission of SARS-CoV-2. To control COVID-19 effectively, Ministry of Public Health announced the policy using Antigen Test Kits (ATK) as fast screen test.
Methods: Descriptive study was conducted, focusing in those who had the positive result of ATK compared to confirmed real time RT-PCR of SARS-CoV-2. The sampling technique was purposive sampling. These samples were classifies as suspected case and close contact cases who visited at Rajamangala National Stadium and Thupatemi Royal Thai Air Force Sports Stadium during 22nd–28th July 2021 for 2,445 cases.
Results: Sampling had both ATK and Real time RT-PCR results with false negative 82 cases (11.5%), false positive 23 cases (1.34%). Incubation period was between 0 to 14 days and median for 5 days. The sensitivity of ATK was 95.36% (95%CI, 91.06–96.96%), the specificity was 96.60% (95%CI, 93.26–97.56%) and the accuracy was 95.71% (95%CI, 94.11-97.31%) respectively. The Positive Predictive Value (PPV) and Negative Predictive Value (NPV) were 98% and 88%, respectively. The prevalence of SARS-CoV-2 infection was 10% in high risk contact.
Conclusion: This study showed that ATK has significant effective results for active case finding at high prevalence area. However, in high risk group cases who had negative ATK results, we need to confirm Real time RT-PCR for the utmost outcome controlling the spreading of COVID-19.