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.

After COVID-19 infects the human body, it will first reproduce in the respiratory system, so we can judge whether the human body is infected with the virus by detecting the virus nucleic acid in sputum and nasopharyngeal swab. Therefore, positive nucleic acid detection can be used as a new standard for the diagnosis of novel coronavirus infection.

Principle of nucleic acid detection

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 novel coronavirus appeared, scientists in China completed the analysis of the whole genome sequence of novel coronavirus in a short time.

Compared with other species' genome sequences, novel coronavirus's specific nucleic acid sequence was found. 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.