LAUSR

BACKGROUND Widespread testing for SARS-CoV-2 is necessary to curb the spread of COVID-19, but is undermined when the only option is a nasopharyngeal swab. Self-collected swab techniques can overcome many of the disadvantages of a nasopharyngeal swab, but require evaluation. METHODS Three self-collected non-nasopharyngeal swab techniques (saline gargle, oral swab and combined oral-anterior nasal swab) were compared to a nasopharyngeal swab for SARS-CoV-2 detection at multiple COVID-19 assessment centers in Toronto, Canada. The performance characteristics of each test were assessed. RESULTS The adjusted sensitivity of the saline gargle was 0.90 (95% CI 0.86-0.94), the oral swab was 0.82 (95% CI 0.72-0.89) and the combined oral-anterior nasal swab was 0.87 (95% CI 0.77-0.93) as compared to a nasopharyngeal swab, which demonstrated a sensitivity of around 90% when all positive tests were the reference standard. The median cycle threshold values for the SARS-CoV-2 E-gene for concordant and discordant saline gargle specimens were 17 and 31 (p<0.001), for the oral swabs were 17 and 28 (p<0.001) and oral-anterior nasal swabs were 18 and 31 (p=0.007). CONCLUSIONS Self-collected saline gargle and an oral-anterior nasal swab have a similar sensitivity to a nasopharyngeal swab for the detection of SARS-CoV-2. These alternative collection techniques are cheap and can eliminate barriers to testing, particularly in underserved populations.