Nucleic acid CT value (Cycle Threshold), i.e. cycle threshold, is used to indicate the amount of viral content.The lower the CT value, the more viral content of the original specimen, and the CT value is used to determine whether or not it is infected by the virus. Nucleic acid CT value refers to the detection of nucleic acid, in real-time fluorescence quantitative PCR technology detection, the nucleic acid of the virus after denaturation, annealing, extension of the three steps of amplification, in the fluorescence to reach a preset concentration of the number of cycles experienced. If the original concentration is high, the number of cycles required to reach the set concentration is low. Therefore, by looking at the CT value of the nucleic acid in each specimen, it is possible to determine whether or not the human body is infected with the virus. Currently, nucleic acid testing of body fluids or tissue specimens by molecular biotechnology is a common method.