LAUSR

PCR tests using nasopharyngeal specimens are highly sensitive for detecting the SARS-CoV-2 virus but can remain positive well beyond the infectious period. This study demonstrated that mid-turbinate specimens can be used to reliably detect asymptomatic infections with less discomfort and provide an effective alternative to nasopharyngeal specimens. Objective The aim of this study was to determine whether mid-turbinate specimens reliably detect active infection in asymptomatic adults undergoing regular COVID-19 PCR testing. Methods Qualitative agreement between 2481 paired nasopharyngeal and mid-turbinate PCR results was assessed. Mean cycle threshold values for each positive result were evaluated as an indicator of active infection. Results Overall agreement between nasopharyngeal and mid-turbinate tests was 98.4%. Positive percent agreement was 37.2%, and negative percent agreement was ~100%. Test pairs with lower cycle thresholds (≤30 and ≤25) reached 67% and 100% positive percent agreement, respectively. Conclusions SARS-CoV-2 infections with high viral loads were detected regardless of specimen type. Mid-turbinate swabs reduced staff discomfort and may decrease repeated positive test results weeks or months after initial infection. Discordant pairs generally had high cycle threshold values (>30) indicating low viral load and little risk of transmitting COVID-19.