Fig. 1: Schematic overview of SARS-CoV-2 RT-PCR testing procedure.
From: Massive and rapid COVID-19 testing is feasible by extraction-free SARS-CoV-2 RT-PCR
The currently widely used procedure for COVID-19 testing involves: a Collection of patient material and deposition of potential SARS-CoV-2 viral particles in transport medium. b Inactivation of the virus by detergent/chaotropic reagents or by heating. c RNA extraction. d, e Transfer to PCR-plate (96/384-well) format in which cDNA synthesis by RT and detection by qPCR may take place. Alternatively, detection can be made by sample barcoding and high-throughput DNA sequencing. f, g Unlike the widely used approach, which includes an RNA extraction step (c) using industrial RNA extraction kits, direct sample testing circumvents this process by omitting extraction. Instead, after clinical samples are deposited in transport medium, viral particles are inactivated either through heating or by direct lysis in detergent-containing buffer. The inactivated samples are then used for the downstream RT-PCR diagnostic reaction.
