SARS-CoV-2 saliva testing is a useful tool for Covid-19 diagnosis

SARS-CoV-2 is the etiologic agent of coronavirus disease 2019 (COVID-19) and is mainly detected by RT-PCR methods from upper respiratory specimens, as recommended by the World Health Organization. Oro/nasopharyngeal swabbing can be discomfortable to the patients, requires trained healthcare personnel and may generate aerosol, increasing the risk of nosocomial infections. In this study, we describe two SARS-CoV-2 RNA extraction-free single RT-PCR protocols on saliva samples and compared the results with the paired oro/nasopharyngeal swab specimens from 400 patients. The two saliva protocols demonstrated a substantial agreement when compared to the oro/nasopharyngeal swab protocol. Moreover, the positivity rate of saliva protocols increased according to the disease period. The 95 % limit of detection of one of the therefore implemented saliva protocol was determined as 9441 copies/mL. Our results support the conclusion that RNA extraction-free RT-PCR using self-collected saliva specimens is an alternative to nasopharyngeal swabs, especially in the early phase of symptom onset.