Antigen detection is the detection of viral antigens and corresponding antibodies to determine whether a certain virus has invaded the human body. 1. Antigen test: clinically, in order to know whether there is some kind of viral infection, we need to do the test of antigen, which refers to the shell of the virus, the method is convenient and fast, and can be used as a means of early screening. For example, the antigen of hepatitis B virus or the antigen of the new coronavirus, when the antigen is positive, it means that there is such a virus infection at present. 2. Antibody test: after human body is infected with a certain virus or injected with vaccine, corresponding antibody can be produced to clear the virus and protect the organism. Antibody testing can confirm the presence of the virus in the body, or previous infection with the virus, or injection of the relevant vaccine, etc. If certain groups of people are suspected of having certain infectious diseases, they can be tested for antibodies. If certain people are suspected of having certain infectious diseases, it is necessary to do the relevant antigen and antibody tests, so as not to be negligent and avoid missing certain infectious diseases and making mistakes.