Evaluation of automated antigen detection test for detection of SARS-CoV-2

Mak, Gannon CK; Lau, Stephen SY; Wong, Kitty KY; Chow, Nancy LS; Lau, CS; Ng, Ken HL; Lam, Edman TK; Chan, Rickjason CW; Tsang, Dominic NC

Background and objective: RT-PCR is the gold standard to detect SARS-CoV-2, however, its capacity is limited. We evaluated an automated antigen detection (AAD) test, Elecsys SARS-CoV-2 Antigen (Roche, Germany), for detecting SARS-CoV-2. Results: We compared the limit of detection (LOD) between AAD, rapid antigen detection (RAD) test, SARS-CoV-2 Rapid Antigen Test (SD Biosensor, Korea), and in-house RT-PCR test. LOD results showed that the AAD test was 100 fold more sensitive than the RAD test, while the sensitivity of the AAD test was comparable to the RT-PCR test. The AAD test detected between 85.7% and 88.6% of RT-PCR-positive specimens collected from COVID-19 patients, false negative results were observed for specimens with Ct values >30. Conclusions: Although clinical sensitivity for the AAD test was not superior or comparable to the RT-PCR test in the present study, the AAD test may be an alternative to RT-PCR in terms of turn-around time and throughput.