Analytical sensitivity and clinical sensitivity of the three rapid antigen detection kits for detection of SARS-CoV-2 virus

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

BACKGROUND: Numerous rapid antigen detection (RAD) kits for diagnosing COVID-19 patients are available in the market recently. OBJECTIVE: To compare analytical sensitivity and clinical sensitivity for the three commercially available RAD kits. STUDY DESIGN: Analytical sensitivity for the detection of SARS-CoV-2 virus was determined by limit of detection (LOD) using PCR as a reference method. Clinical sensitivity was evaluated by using respiratory specimens collected from confirmed COVID-19 patients. RESULTS: The LOD results showed that the three RAD kits varied 102 to 105 fold less sensitive than RT-PCR. Clinical sensitivity of RAD kits ranged from 22.9% to 71.4% for detecting specimens from COVID-19 patients. CONCLUSIONS: Although RAD kits were less sensitive than RT-PCR, understanding the clinical characteristics of different RAD kits can guide us to obtain suitable specimens for testing. The likelihood of positive results for RAD kits will be higher.