There is generally no minimum time to detect HIV infection, and the detection rate is higher for those who test late. However, if the test is still negative 12 weeks after infection, HIV infection can be basically ruled out. However, since it takes 2-4 weeks for antibodies to reach a certain concentration after the virus has invaded the body, and up to 8-12 weeks for some patients, there is a certain window period for antibody detection reagents, i.e. it takes a certain amount of time after infection to be detected, and this time varies among individuals and is also related to the detection reagents. According to previous testing methods, a negative test can be performed up to 3 months after the occurrence of high-risk behavior before it can be ruled out, while with the new generation of testing methods, the shortest detection time is 2 weeks, such as 6-8 weeks, and the accuracy rate is close to 100%, i.e., those who have been infected for a long time have a higher antibody concentration and a higher accuracy rate. If high-risk behavior (such as unclean sex) occurs, the earlier the test is performed during the window period (2-12 weeks), the better, in order to provide timely treatment.