With the use of scientific testing methods in specialized institutions, the probability of HIV antibody results remaining negative after 115 days can rule out the risk of infection. According to the Diagnostic Criteria for AIDS and HIV Infection, the window period for HIV antibody, antigen and nucleic acid detection by existing diagnostic techniques is about 3 weeks, 2 weeks and 1 week respectively after infection, i.e., the test can be performed after 3 weeks of HIV infection. Confirmation of the HIV diagnosis relies on the HIV antibody screening test and the HIV supplementation test. Failure to detect relevant HIV antibodies after 115 days generally rules out infection with a high probability. Therefore, a negative screening test and a negative supplemental test indicate that HIV is not present in the body, but the test should be performed at a specialized CDC to ensure the accuracy of the data.