Saliva - based testing for SARS-CoV-2 diagnosis

Historically, nasopharyngeal sampling has been considered the gold standard for the detection of most upper respiratory tract infections, however major medical and laboratory supply chain issues limited testing capacity early in the COVID-19 pandemic. The need for alternate mass testing strategies placed saliva- based diagnostics into the spotlight. We have shown that SARS-CoV-2 RNA can be detected in saliva from COVID-19 symptomatic and asymptomatic individuals with comparable sensitivity to nasopharyngeal swabs. Additionally, this viral RNA has shown to be stable at room temperature for prolonged periods in saliva. In response to the urgent need for increased capacity for affordable SARS-CoV-2 testing, we developed SalivaDirect protocol, an open source, saliva-based, nucleic-acid-extraction-free, qRT-PCR method for SARS-CoV-2 detection. Raw saliva is used for this protocol, allowing for the use of generic tubes for sample collection. The exclusion of nucleic acid extraction and flexibility in reagents, instruments and sample collection devices required reduces the testing costs to approximately $1.21–4.39 per sample. SalivaDirect offers a sensitive, noninvasive, low-cost alternative to traditional testing, allowing for increased testing capacity, especially in economically challenged environments.

Learning Objectives:

1. Assess the pros and cons of saliva-based COVID-19 testing.

2. Explore different saliva collection and processing workflows.