The best time to test for p24 antigen is 2-6 weeks after infection.
The p24 antigen is the core part of the HIV virus. Testing for the presence of the p24 antigen in the blood can help in the early diagnosis of AIDS. After the human body is infected with HIV, the virus can multiply within 1 week and stimulate the body to produce antibodies, which can reach a high concentration in about 4 weeks, at which time the infection can be detected by the combined antigen-antibody reagent. If the test is negative at 4 weeks, it can be re-tested at 6 weeks, and if it is still negative, it can be basically excluded. In addition, p24 antigen detection time is earlier than antibody detection time, such as HIV infection, using the latest generation of detection methods, can be detected in 2 weeks, if negative, in 4-6 weeks again to test.
After the test, if the p24 antigen is positive, it indicates HIV infection and the patient can go through the acute infection phase, asymptomatic infection phase and AIDS phase, and early treatment can slow down the development to AIDS phase.