The substance of nucleic acid detection is the nucleic acid of virus. Nucleic acid detection is to determine whether the patient is infected by COVID-19 by detecting whether there is nucleic acid of foreign invasive virus in respiratory tract samples, blood or feces. Therefore, once the nucleic acid is "positive", it can prove that there is a virus in the patient.
On March 22, 2022, the National Health and Wellness Committee issued the Implementation Guide for Regional novel coronavirus Nucleic Acid Testing Institutions (Third Edition), which revised the "all personnel" in the second edition of the guide to "regions", and the size of the regions was determined by the needs of epidemic prevention and control; It is emphasized that nucleic acid detection should have a clear goal, be targeted and not be "one size fits all". All living things contain nucleic acids, including DNA and RNA. Novel coronavirus is a virus containing only RNA, and the specific RNA sequence in the virus is a sign to distinguish the virus from other pathogens. After the appearance of novel coronavirus, Chinese scientists completed the analysis of the whole genome sequence of novel coronavirus in a very short time, and found the specific nucleic acid sequence in novel coronavirus by comparing with the genome sequences of other species. If novel coronavirus's specific nucleic acid sequence can be detected in patients' samples during clinical laboratory testing, it should be suggested that patients may be infected by novel coronavirus.