Field-deployable, rapid diagnostic testing of saliva for SARS-CoV-2
Shan Wei, Hemant Suryawanshi, Alexandre Djandji, Esther Kohl, Stephanie Morgan, Eldad A. Hod, Susan Whittier, Kevin A. Roth, Raymond T. Yeh, Juan Carlos Alejaldre, Elaine Fleck, Stephen A. Ferrara, Daniel Hercz, David Andrews, Lilly Lee, Kristopher A. Hendershot, Joshua Goldstein, Yousin Suh, Mahesh Mansukhani, Zev Williams
Abstract
To safely re-open economies and prevent future outbreaks, rapid, frequent, point-of-need, SARS-CoV-2 diagnostic testing is necessary. However, existing field-deployable COVID-19 testing methods require the use of uncomfortable swabs and trained providers in PPE, while saliva-based methods must be transported to high complexity laboratories for testing. Here, we report the development and clinical validation of High-Performance Loop-mediated isothermal Amplification (HP-LAMP), a rapid, saliva-based, SARS-CoV-2 test with a limit of detection of 1.4 copies of virus per µl of saliva and a sensitivity and specificity with clinical samples of > 96%, on par with traditional RT-PCR based methods using swabs, but can deliver results using only a single fluid transfer step and simple heat block. Testing of 120 patient samples in 40 pools comprised of 5 patient samples each with either all negative or a single positive patient sample was 100% accurate. Thus, HP-LAMP may enable rapid and accurate results in the field using saliva, without need of a high-complexity laboratory.