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

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 (COVID-19). In this study, the use of oral rinses and posterior oropharyngeal saliva as an alternative to swab collection methods from symptomatic and asymptomatic healthcare workers for the detection of SARS-CoV-2 RNA by RT-PCR was evaluated. For saliva samples, the overall agreement with oropharyngeal swabs (OPS) 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%). Oral rinses were compared with NPS 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 higher than 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 4ºC. While the dilution of SARS-CoV-2 in oral rinses precluded its acceptability as a sample type, posterior oropharyngeal saliva was an acceptable alternative sample type for SARS-CoV-2 RNA detection.

Diagnosis of SARS-Cov-2 Infection by RT-PCR Using Specimens Other Than Naso- and Oropharyngeal Swabs: A Systematic Review and Meta-Analysis

“…Overall, twenty-one studies had low risk of bias (63.6%) [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 35 , 38 , 39 , 40 , 41 , 42 , 43 ], eleven raised some concerns (33.3%) [ 21 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 36 ] and one had high risk of bias (3.0%) [ 37 ] ( Figure 2 ) (fully detailed in Supplementary S3 , pp. 12).…”

“…Aiming at simplifying the sample collection procedure, so that the average person could perform self-sampling, alternative specimens have been tested for the detection of SARS-CoV-2, namely sputum, saliva, tears/conjunctival swab (CS), feces, rectal swab, urine, breast milk, and semen [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 ]. To the best of our knowledge, until now, just one protocol for saliva testing, the SalivaDirect, has been approved by a public health authority, the United States Food and Drug Administration (FDA) [ 44 ].…”

Screening for SARS-CoV-2 by RT-PCR: saliva or nasopharyngeal swab? Systematic review and meta-analysis

“…In the context of mass screening, most participants are asymptomatic. Among the 49 studies analysed, only one included exclusively asymptomatic participants 67 and 8 studies both symptomatic and asymptomatic participants but it was impossible to separate the data between the two populations 18,21,26,29,51,56,64,66 . One study of contact cases included a larger number of asymptomatic subjects as compared to study of symptomatic subjects 49 .…”

Relative Sensitivity of Saliva and Upper Airway Swabs for Initial Detection of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in Ambulatory Patients

“…The low numbers of positive specimens identified in these studies limits confidence in any conclusion of superiority for saliva, but support the conclusion that saliva sampling is sufficiently sensitive for screening, as does a study that appeared after the inclusion period for this systematic review. 32 …”