Self-Collection of Nose and Throat Swab Samples for SARS-CoV-2 Antigen Testing

Key Messages

• The emergence of new variants of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has raised questions about the accuracy of currently available rapid antigen detection tests (RADTs) for the detection of these variants using the currently authorized sampling methods.
• Six Canadian provinces and 2 international jurisdictions have formally recommended people swab both their throat and nose when performing a RADT in response to the emergence of the Omicron variant. The evidence used to support these decisions was not clearly reported.
• Three pre-print non-peer reviewed publications (1 from Canada, 2 from the Netherlands) were identified regarding the diagnostic accuracy and clinical utility of RADTs using dual nasal and throat self-collected sample for suspected COVID-19. No relevant studies were identified that included children younger than 16 years old.
• Findings from these publications indicate that using self-collected combined nasal plus throat samples, instead of self-collected nasal samples for RADTs, resulted in greater detection rates without impacting true negative rates. Furthermore, combined nasal plus throat sampling is associated with high participant acceptability and tolerability, ease of use, and low incidence of harms (when reported). However, the limitations of these publications (e.g., non-peer reviewed pre-prints; dual nasal and throat sampling with swabs approved for nasal sampling only) should be taken into consideration when interpreting these findings.
• As new variants emerge and real-world clinical evaluations are published, regulatory bodies and/or RADT manufacturers could consider reassessing sampling methods, suitable swab types, and testing instructions.