FIGURE 2.

Workflow of SARS-CoV-2 nucleic acid detection. The whole detection process can be divided into three parts: sample preparation, amplification, and nucleic acid testing. Sample preparation included sample collection and RNA extraction. Specimens mainly come from people (such as nasal swabs and throat swabs) and the environment (such as the surface of packages). RNA can be extracted from deactivated virus, and then cDNAs are synthesized based on reverse transcriptase. Various nucleic acid amplification methods, including RT-PCR, isothermal amplification, CRISPR, and biosensors, can be applied to amplify and detect cDNAs.