Evaluation of rapid antigen test for detection of SARS-CoV-2 virus

Mak, Gannon CK; Cheng, Peter KC; Lau, Stephen SY; Wong, Kitty KY; Lau, CS; Lam, Edman TK; Chan, Rickjason CW; Tsang, Dominic NC

BACKGROUND: The rapid diagnosis of COVID-19 patients is essential to reduce the disease spread. Rapid antigen detection (RAD) tests are available, however, there is scanty data on the performance of RAD tests. OBJECTIVE: To evaluate the performance of BIOCREDIT COVID-19 Ag test and compared it with real-time RT-PCR for detecting SARS-CoV-2 virus. Study Design: Analytical sensitivity for the detection of SARS-CoV-2 virus was determined for the RAD test using viral culture and PCR as a reference methods. The RAD test was further evaluated using respiratory samples collected from confirmed COVID-19 patients. The results were compared with RT-PCR test. RESULTS: The detection limits between RAD test, viral culture and PCR varied hugely. RAD was 103 fold less sensitive than viral culture while RAD was 105 fold less sensitive than RT-PCR. The RAD test detected between 11.1% and 45.7% of real-time RT-PCR-positive samples from COVID-19 patients. CONCLUSIONS: This study demonstrated that the RAD test serve only as adjunct to RT-PCR test because of potential for false-negative results.