Litchi News Beijing Work Department Reporter / Kou Cheng
On the afternoon of March 15, the joint prevention and control mechanism of the State Council held a press conference on the situation related to epidemic prevention and control and vaccination work.
In view of the difference between antigen detection and nucleic acid detection, Li Jinming, deputy director of the Clinical Laboratory Center of the National Health Commission, introduced that antigen detection is to detect antigens through the binding reaction of antigen antibodies, which is characterized by rapid and simple. To use a popular analogy, the colloidal gold test strip method is the usual method of pregnancy experiments, the method is more similar, and the operation is very simple.
However, because nucleic acid detection has a process of amplification, it is exponential amplification, so the sensitivity of nucleic acid detection is 100 to 1000 times higher than that of antigen detection.
Li Jinming said that if a person is infected with the new crown virus, the virus content in the pharynx has a process from less to more, if the amount reaches 1 million or even 10 million per milliliter, at this time, the relevant key populations are added to antigen screening, most people can make it, so that the spread of the epidemic can be quickly controlled.
In addition, if antigen detection and nucleic acid detection are compared, its specificity is not the same. The specificity of antigen detection can reach 99%, but the specificity of nucleic acid detection is 100% in terms of methodology, that is, nucleic acid detection has no false positive in methodology, so nucleic acid detection has always been a basis for us to determine new crown infection, a "gold standard".
Therefore, antigen detection is not a substitute for nucleic acid testing. When the antigen test is positive, be sure to confirm with a nucleic acid test. However, the nucleic acid test is positive, and regardless of whether the antigen test is negative or positive, the person being tested must be treated as a new crown infection or a confirmed patient.
In addition, Li Jinming also said that antigen testing should be used in high-risk, high-prevalence cluster infection population testing, our general population should not do antigen testing at will.