The latest time that HIV infection can be detected is related to the method of testing and the time when the patient develops antibodies.
AIDS is caused by the human immunodeficiency virus (HIV), which multiplies about 1-2 weeks after entering the body and can be diagnosed by testing for viral antigens and antibodies. The core of the virus carries the p-24 antigen, which can be detected about 2 weeks after infection; a sufficient amount of antigen can stimulate the body to produce antibodies to the virus, which takes about 4-8 weeks from the time of infection to the appearance of positive serum; some patients can remain negative for 2-3 months. Therefore, if the viral antigen is detected, the result is detected relatively early, usually about 2 weeks; if the antibody is detected, it is 8 weeks or 3 months at the latest. If the antibody test is still negative 8 weeks after the occurrence of high-risk behavior, the infection can be basically ruled out, and if the antibody test is still negative at 3 months, the infection can be ruled out.
After high-risk behavior (such as unsafe sex, intravenous injection, blood transfusion, etc.), it is recommended to seek early diagnosis from the Infectious Diseases Department or the Venereal Disease Department.