Practical challenges to the clinical implementation of saliva for SARS-CoV-2 detection

Abstract

Due to global shortages of flocked nasopharyngeal swabs and appropriate viral transport media during the COVID-19 pandemic, alternate diagnostic specimens for SARS-CoV-2 detection are sought. The accuracy and feasibility of saliva samples collected and transported without specialized collection devices or media were evaluated. Saliva demonstrated good concordance with paired nasopharyngeal swabs for SARS-CoV-2 detection in 67/74 cases (90.5%), though barriers to saliva collection were observed in long-term care residents and outbreak settings. SARS-CoV-2 RNA was stable in human saliva at room temperature for up to 48 h after initial specimen collection, informing appropriate transport time and conditions.

Keywords: COVID-19; Nasopharyngeal; SARS-CoV-2; Saliva; Transport.

Fig. 1

Saliva samples from patients with known COVID-19 infection or from healthy volunteers spiked with viral transport media from the nasopharyngeal swabs of known positive COVID-19 cases were held in the laboratory at room temperature and processed at different time points. The stability of SARS-CoV-2 viral RNA in these samples is represented by the average detected cycle threshold (Ct) value of the Envelope (E) gene of SARS-CoV-2 tested in triplicate and plotted over time. Patient 1 was unable to provide sufficient sample volume for five readings and was only tested up to 24 h after the initial time of collection