Diagnostic Performance of SARS-CoV-2 Rapid Antigen Test in Relation to Realtime - PCR Ct (Cycle threshold) Value

Abstract

The outbreak of SARS-Cov-2 is more widespread very fast around the world. SARS-Cov-2 infection can be diagnosed with a simple, rapid and accurate test method. To evaluate the performance of the SARS-CoV-2 Rapid test kit, It is important to compare it to the Real-time RT-PCR method, which is the standard method for diagnosing COVID-19. The VTRUST Antigen test kit was utilized in this study to analyze Nasopharyngeal swab samples from 368 patients suspected of being infected when they visited Hat Yai Hospital.There were 163 positive results and 205 negative results. The results of the SARS-CoV-2 antigen diagnostic performance test with the relationship between Ct values by RT-PCR method. We found that Positive results by SARS-CoV-2 antigen method when confirmed by Real-time RT-PCR method found the target gene ORF1ab with an average cycle threshold (Ct) value of 18.6 ± 3.8, the N gene with an average cycle threshold (Ct) value of 17.6 ± 3.87 and the E gene with an average cycle threshold (Ct) value of 18.03 ± 3.81. There were 12 reported negative results but confirmed as positive byReal-time RT-PCR method with the target gene ORF1ab with an average cycle threshold (Ct) value of 33.05 ± 3.86 (min 23.28, max 37.47) the N gene with an average cycle threshold (Ct) value of 31.99 ± 3.31 (min
23, max 35.12) and the E gene with an average cycle threshold (Ct) value of 32.36 ± 3.88 (min 22.97, max 37.42)
has a sensitivity and specificity of 93.10%, 99.48% respectively. The efficiency of the SARS-CoV-2 Rapid test kit
with a sensitivity and specificity can be used to screen infected people well, helping to control the spread of
the covid-19 virus.