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. 2021 Feb 1;72(3):482-485.
doi: 10.1093/cid/ciaa759.

Performance of Oropharyngeal Swab Testing Compared With Nasopharyngeal Swab Testing for Diagnosis of Coronavirus Disease 2019-United States, January 2020-February 2020

Monita R Patel  1 , Darin Carroll  1 , Emily Ussery  1 , Hilary Whitham  1 , Christopher A Elkins  1 , Judith Noble-Wang  1 , James Kamile Rasheed  1 , Xiaoyan Lu  1 , Stephen Lindstrom  1 , Virginia Bowen  1 , Jessica Waller  1 , Gregory Armstrong  1 , Susan Gerber  1 , John T Brooks  1
Affiliations

Performance of Oropharyngeal Swab Testing Compared With Nasopharyngeal Swab Testing for Diagnosis of Coronavirus Disease 2019-United States, January 2020-February 2020

Monita R Patel et al. Clin Infect Dis. .

Abstract

Among 146 nasopharyngeal (NP) and oropharyngeal (OP) swab pairs collected ≤7 days after illness onset, Real-Time Reverse Transcriptase Polymerase Chain Reaction assay for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2 RT-PCR) diagnostic results were 95.2% concordant. However, NP swab cycle threshold values were lower (indicating more virus) in 66.7% of concordant-positive pairs, suggesting NP swabs may more accurately detect the amount of SARS-CoV-2.

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

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Figures

Figure 1.
Figure 1.
Slope graph of NP–OP swab pair severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) testing Ct values by concordance/discordance of Centers for Disease Control and Prevention DC 2019-Novel Coronavirus Real-Time Reverse Transcriptase-Polymerase Chain Reaction Diagnostic Panel diagnostic results (n = 146). The dot on the left of each panel represents the NP swab, and the dot on the right of each panel represents the OP swab. The line drawn between 2 dots indicates an NP–OP swab pair. The negative diagnostic result (gray) Ct value is set to the threshold value of 40. The positive diagnostic result (yellow) is defined as a Ct value <40. N1 and N2 represent separate genetic targets tested for the presence of SARS-COV-2 viral RNA. Abbreviations: Ct, cycle threshold; NP, nasopharyngeal; OP, oropharyngeal.
See this image and copyright information in PMC

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