VT Chu et al. JAMA Intern Med. Published online April 29, 2022. doi:10.1001/jamainternmed.2022.1827. Open Access: Comparison of Home Antigen Testing With RT-PCR and Viral Culture During the Course of SARS-CoV-2 Infection

Background: This was a prospective cohort study of 225 adults and children comparing reverse transcription–polymerase chain reaction (RT-PCR)–confirmed SARS-CoV-2 infection with antigen testing (QuickVue At-Home OTC COVID-19 Test) and viral culture (January to May 2021)

Key findings:

• Rapid testing (antigen) sensitivity was 64% and viral culture sensitivity was 84% when compared with same-day RT-PCR and viral culture
• Rapid testing (antigen) sensitivity peaked 4 days after illness onset (77%); a second test 1 to 2 days later showed improved sensitivity (81%-85%)

My take: This study shows that a single rapid test is NOT adequate to exclude SARS-CoV-2 infection, especially if they are symptomatic (need to recheck 1-2 days later if negative rapid test). The reliability/accuracy/sensitivity is likely to vary greatly between different rapid tests and may change significantly with different viral variants.