Performance of oropharyngeal swab testing compared to nasopharyngeal swab testing for diagnosis of COVID-19 -United States, January-February 2020

Clin Infect Dis. 2020 Jun 16;ciaa759. doi: 10.1093/cid/ciaa759. Online ahead of print.

Abstract

Among 146 nasopharyngeal (NP) and oropharyngeal (OP) swab pairs collected ≤7 days since illness onset, CDC real-time RT-PCR SARS-CoV-2 assay diagnostic results were 95.2% concordant. However, NP swab Ct values were lower (indicating more virus) in 66.7% of concordant-positive pairs, suggesting NP swabs may more accurately detect amount of SARS-CoV-2.

Keywords: SARS-CoV-2; coronavirus; cycle threshold values; nasopharyngeal; oropharyngeal; testing.