AIDS, or AIDS, and HIV, or the AIDS virus, should be seen by the CDC promptly if the patient suspects he or she is infected with AIDS and takes blocking medication. Viral testing is also performed after the window period of infection to confirm the infection. The current diagnostic technology detects HIV antibodies, antigens and nucleic acids during the window period of about 3 weeks, 2 weeks and 1 week after infection, respectively. I. HIV antibody detection 1. HIV antibody screening test: detect the presence or absence of HIV antibody in the patient’s serum by enzyme-linked immunosorbent assay, chemiluminescence or immunofluorescence, immunoagglutination, etc. If there is no reaction in the screening test, the patient is negative for HIV antibody. If there is a reaction to the screening test, a positive report is generally not issued, but a retest of HIV antibodies is performed. If there is no reaction in two retests, the test is negative. If there are two reactions in the retest (both reactions or one reaction and one non-reaction), the report is “HIV infection to be determined” and further confirmatory test will be done; 2. HIV antibody confirmatory test: After the antibody screening test is positive, antibody confirmation is needed by immunoblotting and indirect immunofluorescence method. If the test is negative, it can be considered uninfected, but if there is a window period problem, a follow-up test should be performed for diagnosis. If positive, the test result is determined to be HIV-1 or HIV-2, and post-test counseling as well as registration is done. If it is an indeterminate result, nucleic acid test should be done as early as possible or retested after 2-4 weeks. Second, the pathogenic test 1, HIV virus isolation: the preferred patient fresh anticoagulated whole blood, but also can use plasma, semen and other body fluids for testing. If the culture of p24 antigen or reverse transcriptase is always negative twice in a row, it means that the HIV isolation is negative. If the opposite is true, the test is positive. However, it should be noted that a positive test result is HIV infection, but a negative result cannot exclude infection and further testing is required; 2. HIV nucleic acid testing: nucleic acid testing is divided into qualitative and quantitative tests, both of which can be used as diagnostic tests for HIV infection. Reported reaction means positive nucleic acid test, no reaction means negative. Immunological test CD4+ T lymphocyte test: The CD4+ T lymphocyte count or calculation of its percentage of peripheral blood T cells is used to assess the degree of immunodeficiency of patients, and is the main test index for staging HIV infection and AIDS and judging the efficacy of treatment. The results are mainly classified into four levels: no immunodeficiency, mild immunodeficiency, moderate immunodeficiency, and severe immunodeficiency. The current diagnostic principle of AIDS is based on laboratory tests and a combination of clinical as well as epidemiological data for assessment. Among them, HIV antibody and pathogenetic tests are the basis for confirming HIV infection; CD4+ T lymphocyte test and clinical manifestations are the main basis for staging HIV infection diagnosis.