Molecular Diagnostic Tools for the Detection of SARS-CoV-2

The pandemic causing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has globally infected more than 50 million people and similar to 1.2 million have succumbed to this deadly pathogen. With the vaccine trials still in clinical phases, mitigation of Coronavirus Disease 2019 (COVID-19) relies primarily on robust virus detection methods and subsequent quarantine measures. Hence, the importance of rapid, affordable and reproducible virus testing will serve the need to identify and treat infected subjects in a timely manner. Based on the type of diagnostic assay, the primary targets are viral genome (RNA) and encoded proteins. Currently, COVID-19 detection is performed using various molecular platforms as well as serodiagnostics that exhibit approximately 71% sensitivity. These methods encounter several limitations including sensitivity, specificity, availability of skilled expertise and instrument access. Saliva-based COVID-19 diagnostics are emerging as a superior alternative to nasal swabs because of the ease of sample collection, no interaction during sampling, and high viral titers during early stages of infection. In addition, SARS-CoV-2 is detected in the environment as aerosols associated with suspended particulate matter. Designing virus detection strategies in diverse samples will allow timely monitoring of virus spread in humans and its persistence in the environment. With the passage of time, advanced technologies are overcoming limitations associated with detection. Enhanced sensitivity and specificity of next-generation diagnostics are key features enabling improved prognostic care. In this comprehensive review, we analyze currently adopted advanced technologies and their concurrent use in the development of diagnostics for SARS-CoV-2 detection.