AIDS cannot be ruled out at 3 weeks. The period of time between HIV infection and the production of antibodies in the blood that can be detected is called the window period, and for the tests currently used in most hospitals, the window period is generally between 2 and 6 weeks, with a very small number of patients having a window period of up to 3 months. Patients infected with HIV may test negative during the window period. 3 weeks does not exceed the upper limit of the window period, so AIDS cannot be ruled out. It is usually necessary to test after the window period and retest again, if both results are negative, before HIV infection can be completely ruled out. AIDS is still incurable, so prevention is more important than treatment. Avoid high-risk behaviors and establish a correct awareness of HIV prevention. If you have high-risk behaviors, it is recommended that you consult a doctor for testing.