Viral Transport Media (VTM) Pooling To Scale-Up COVID-19 Diagnostics: Resource Optimization at Population Level Screening

Abstract

Background: The threat of coronavirus disease 2019 (COVID-19) is still looming large on humankind. Pooled-testing can serve as a method of choice for current and future mass surveillance. The aim is to economically benefit in the face of resource-paucity in overburdened public health systems. Methods: This study assesses the viability of pooled-testing with viral transport media (VTM) for COVID-19 diagnosis. For this, we designed high-dilution pools using samples with wide-ranging viral loads. The testing employs common TaqMan-based RT-PCR assay considering biological as well as technical replicates. Results: We successfully detected a single positive sample in a pool (up to 1/32 dilutions) without loss of sensitivity. The results from biological and technical replicates were found to be satisfactory and reproducible for the objective. We have also discussed multiple variables that can influence the final outcome of pooled testing strategy. Conclusions: We show that pooling approach can be efficiently applied for the detection of SARS-CoV-2. We report improved pooling success compared to published studies, even with very low input volume of media, in very high pool-sizes using low-viral load samples. We consider these features to be unique to this study. The study outcomes are encouraging and can be implemented in public health settings to conserve precious resources.