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.
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