Rapid SARSـCoVـ2 Antigen Detection Assay versus Real-timeـPCR Assay for Laboratory Detection of COVID-19

Abstract

Background: real-time polymerase chain reaction (RT-PCR) of nasal/oropharyngeal samples is the gold standard in detecting SARS-CoV-2 infection, however, it has a long turnaround time. Objectives: To meet the growing epidemic demand, we evaluated the performance of rapid SARS-CoV-2 antigen tests in detecting COVID-19 infection compared to RT-PCR. Patients and Methods: a cross-sectional study involving adults suspected to have mild or moderate COVID-19 infection severity scores over 6 months from 1/10/2021 to 1/4/2022. Results: from 186 patients assessed, 88(47.3%) males and 98 (52.7%) females with a mean age of 52.55 ± 20.15 years, and a mean disease duration of 13.1± 4.5 days. 57(30.6%) cases of RT-PCR were positive and 129(69.4%) cases were negative. Meanwhile, in rapid antigen tests, 49(26.34%) cases were positive and 137(73.35%) cases were negative. The receiver operator characteristic (ROC) curve predicts the performance of rapid antigen tests revealing an overall agreement with the RT-PCR results, with 85% sensitivity (95% CI, 73.43% - 92.90 %), 98.54% specificity (95% CI, 94.83% - 99.82%), 96.23% PPV (95% CI, 86.52% - 99.02%), 93.75% NPV (95% CI= 89.14% - 96.48%), 94.42% accuracy (95% CI, 90.23% - 97.18%), and with 0.918 the area under the curve. Conclusion: Although RT-PCR is still the gold standard for detecting SARS-CoV-2 infections, the rapid SARS-CoV-2 antigen test offers good sensitivity, specificity, PPV, NPV, and a significantly short turnaround time. As a result, it has great clinical utility as a primary frontline test for detecting infected patients in an emergency setting.

Keywords

• viruses diagnostic challenges
• rapid sarsـcovـ2 antigen
• rt-pcr