Discussion
throat
This randomized clinical trial found that the sensitivity of SARS-CoV-2 rapid antigen testing was significantly higher for HCW-collected throat specimens compared with HCW-collected nasal specimens. In contrast, the self-collected nasal specimens had higher sensitivity than the self-collected throat specimens for symptomatic participants. Adding a throat swab to the standard practice of a single nasal swab may improve sensitivity for HCW-collected and self-collected specimens for rapid antigen testing.To our knowledge, our study is the first to demonstrate that HCW-collected throat specimens for COVID-19 rapid antigen testing have a significantly higher sensitivity than HCW-collected nasal specimens. Our results contrast with a prior study finding that throat specimens had a lower sensitivity of 36.8% (compared with 69.4% in our study) for rapid antigen testing.In contrast to the higher SARS-CoV-2 detection rate for both rapid antigen and RT-PCR testing of HCW-collected throat specimens compared with HCW-collected nasal specimens, we found a lower mean Ct value for HCW-collected nasal specimens compared with HCW-collected throat specimens. Our subgroup analysis also revealed that the higher sensitivity of rapid antigen and RT-PCR testing of throat specimens compared with nasal specimens was primarily driven by asymptomatic participants and those with a low viral load (Ct values of 20-34). A study conducted before the Omicron variant also found higher molecular detection of SARS-CoV-2 in throat specimens compared with nasopharyngeal specimens for asymptomatic participants.In agreement with other studies,