Here, we develop a simple molecular test for SARS-CoV-2 in saliva based on reverse transcription loop-mediated isothermal amplification (RT-LAMP). The test has two steps: 1) heat saliva with a stabilization solution, and 2) detect virus by incubating with a primer/enzyme mix. After incubation, saliva samples containing the SARS-CoV-2 genome turn bright yellow. Because this test is pH dependent, it can react falsely to some naturally acidic saliva samples. We report unique saliva stabilization protocols that rendered 295 healthy saliva samples compatible with the test, producing zero false positives. We also evaluated the test on 278 saliva samples from individuals who were infected with SARS-CoV-2 but had no symptoms at the time of saliva collection, and from 54 matched pairs of saliva and anterior nasal samples from infected individuals. The Saliva TwoStep test described herein identified infections with 94% sensitivity and >99% specificity in individuals with sub-clinical (asymptomatic or pre-symptomatic) infections.
All data generated or analyzed during this study are included in the manuscript and supporting files.
- Nicholas R Meyerson
- Sara L Sawyer
- Sara L Sawyer
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Human subjects: This study was approved by the University of Colorado Boulder Institutional Review Board. Saliva samples for assay development were collected under protocol 20-0068. Adult participants were consented verbally and donated up to 2mL of whole saliva for use as a reagent in optimization and limit of detection experiments. Data on human subjects is aggregated from University of Colorado Boulder operational COVID-19 surveillance testing activities. For this reason, the research herein did not fall under IRB purview.
- Bavesh D Kana, University of the Witwatersrand, South Africa
© 2021, Yang et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.