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Comparative Study
. 2021 Jan;23(1):3-9.
doi: 10.1016/j.jmoldx.2020.10.018. Epub 2020 Nov 17.

Performance of Severe Acute Respiratory Syndrome Coronavirus 2 Real-Time RT-PCR Tests on Oral Rinses and Saliva Samples

N Esther Babady  1 , Tracy McMillen  2 , Krupa Jani  2 , Agnes Viale  3 , Elizabeth V Robilotti  4 , Anoshe Aslam  4 , Maureen Diver  5 , Desiree Sokoli  5 , Greg Mason  4 , Monika K Shah  4 , Deborah Korenstein  4 , Mini Kamboj  4
Affiliations
Comparative Study

Performance of Severe Acute Respiratory Syndrome Coronavirus 2 Real-Time RT-PCR Tests on Oral Rinses and Saliva Samples

N Esther Babady et al. J Mol Diagn. 2021 Jan.

Abstract

Access to rapid and accurate detection of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA is essential for controlling the current global pandemic of coronavirus disease 2019. In this study, the use of oral rinses (ORs) and posterior oropharyngeal saliva as an alternative to swab collection methods from symptomatic and asymptomatic health care workers for the detection of SARS-CoV-2 RNA by RT-PCR was evaluated. For saliva samples, the overall agreement with oropharyngeal swabs was 93% (Ƙ = 0.84), with a sensitivity of 96.7% (95% CI, 83.3%-99.8%). The agreement between saliva and nasopharyngeal swabs was 97.7% (Ƙ = 0.93), with a sensitivity of 94.1% (95% CI, 73.0%-99.7%). ORs were compared with nasopharyngeal swabs only, with an overall agreement of 85.7% (Ƙ = 0.65), and a sensitivity of 63% (95% CI, 46.6%-77.8%). The agreement between a laboratory-developed test based on the CDC RT-PCR and two commercial assays, the Xpert Xpress SARS-CoV-2 and the Cobas SARS-CoV-2, was also evaluated. The overall agreement was >90%. Finally, SARS-CoV-2 RNA in saliva samples was shown to be stable, with no changes in viral loads over 24 hours at both room temperature and 4°C. Although the dilution of SARS-CoV-2 in ORs precluded its acceptability as a sample type, posterior oropharyngeal saliva was an acceptable alternative sample type for SARS-CoV-2 RNA detection.

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Figures

Figure 1
Figure 1
Comparison of severe acute respiratory syndrome coronavirus 2 cycle threshold (CT) values in oral rinses (ORs) and nasopharyngeal swabs (NPSs). Each circle represents the RT-PCR CT values for the N2 target in individual samples. Black circles are the CT values for NPSs. Blue circles represent CT values for ORs. A: Mean CT values in NPSs compared with mean CT values in ORs. B: Comparison of CT values in each NPS/OR paired sample.
Figure 2
Figure 2
Comparison of severe acute respiratory syndrome coronavirus 2 cycle threshold (CT) values in saliva and oropharyngeal swabs (OPSs). Each circle represents the RT-PCR CT values for the N2 target in individual samples. Black circles are the CT values for OPSs. Blue circles represent CT values for saliva. A: Mean CT values in OPSs compared with mean CT values in saliva. B: Comparison of CT values in each OPS/saliva paired sample.
Figure 3
Figure 3
Comparison of severe acute respiratory syndrome coronavirus 2 cycle threshold (CT) values in saliva and nasopharyngeal swabs (NPSs). Each circle represents the RT-PCR CT values for the N2 target in individual samples. Black circles are the CT values for NPSs. Blue circles represent CT values for saliva. A: Mean CT values in NPSs compared with mean CT values in saliva. B: Comparison of CT values in each NPS/saliva paired sample.
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