Sensitivity of Nasopharyngeal Swabs and Saliva for the Detection of Severe Acute Respiratory Syndrome Coronavirus 2

Abstract

<jats:title>Abstract</jats:title> <jats:p>We enrolled 91 consecutive inpatients with COVID-19 at 6 hospitals in Toronto, Canada, and tested 1 nasopharyngeal swab/saliva sample pair from each patient using real-time RT-PCR for severe acute respiratory syndrome coronavirus 2. Sensitivity was 89% for nasopharyngeal swabs and 72% for saliva (P = .02). Difference in sensitivity was greatest for sample pairs collected later in illness.</jats:p>

<p>Saliva as an Alternative Specimen for Molecular COVID-19 Testing in Community Settings and Population-Based Screening</p>

“…8,14,15 Although most of the indices for diagnostic accuracy in this study are aligned with those reported in similar studies in cohorts of hospitalized COVID-19 patients and symptomatic ambulatory individuals, our sensitivity and positive predictive values are on the lower end. 5,7,9,10 This difference is probably due to clinical heterogeneity in patients (48.6% asymptomatic in our sample). As this study was carried out in a screening center, patients with severe COVID-19 did not form part of our study population.…”

“…4 Neat saliva obtained by the drooling technique, which can be selfcollected without supervision, has been reported to show greater sensitivity compared to NPS in hospitalized COVID-19 patients and at-risk HCW on COVID-19 wards. [5][6][7][8] With the easing of lockdown restriction measures, repeated community-based sampling for rapid tracking of new infections in the population is anticipated and a non-invasive diagnostic specimen such as saliva will be useful for public health surveillance. Studies investigating the use of saliva for SARS-CoV-2 RT-PCR have largely been carried out among COVID-19 in-patients and symptomatic ambulatory patients with most of these studies being underpowered with small sample sizes.…”

Saliva collected in universal transport media is an effective, simple and high-volume amenable method to detect SARS-CoV-2

“…It is noteworthy that our UTM test group were primarily outpatients as opposed to all in Pasomsub et al ) whereas 59% were hospitalized in our gargle group as opposed to 100% in Jamal et al [ 6 ]. Hospitalized patients may have altered saliva composition and production due to co-morbidities and/or multiple medications lowering saliva production and altering saliva composition [ 7 ].…”

“…Like our saline gargle results, Jamal et. al reported a sensitivity of 70% when phosphate-buffered saline (PBS) was added to saliva immediately after collection [ 6 ] (samples were frozen before testing), suggesting saline or PBS may be suboptimal saliva transport media.…”

Saliva in the Diagnosis of COVID-19: A Review and New Research Directions

“…In addition to viral load, the efficiency of saliva collection was investigated and compared with oro-/nasopharyngeal swabs for viral detection. Nine studies reported the sensitivity and/or specificity of RT-qPCR-analyzed saliva specimens as compared with the gold standard diagnosis of throat and nasopharyngeal swabs (NPSs; Azzi, Carcano, Gianfagna, et al 2020;Jamal et al 2020;Leung et al 2020;Nagura et al 2020;Pasomsub et al 2020;Tajima et al 2020;Williams et al 2020;Zhu et al 2020), which varied considerably from 66% to 91.7% and from 97% to 100%, respectively. Combined with those results, the cost savings for posterior oropharyngeal saliva collection were analyzed in 1 study and compared with conventional NPS, with the costs of equipment estimated as US $8.24 per 100 saliva specimens as compared with US $104.87 per 100 NPSs (Wong et al 2020).…”