Blood tests can detect HIV. After 3-4 weeks of being infected with HIV, the blood can be tested for HIV antibodies, and the antibody test is also the initial screening test for HIV. If the antibodies are positive, further confirmatory tests will be done. Generally, more than 90% of people with positive antibodies will have a positive confirmatory test, and the diagnosis can be confirmed only if the confirmatory test is also positive. In addition, the patient’s blood can be collected for HIV-RNA testing, and the results are usually available 7-10 days after HIV infection. If a high-risk situation occurs, do not wait for the test results, but apply blocking drugs immediately. Currently, blocking drugs are available at CDCs in major cities in China as well as at hospitals specializing in HIV treatment.