How soon can you tell that you have HIV?

Generally speaking, it will be between some two to six weeks; but it can take up to three months (the 'window period') for the immune response to be fully triggered and produce enough antibodies to be detected by the HIV antibody test. If you get a negative test result during the three-month window period, you should ideally repeat the test again three months after exposure. If you have become infected, then you may experience symptoms of HIV seroconversion illness when your immune response kicks in. This illness generally takes the form of a mild fever / sore throat / rash / mild flu-like illness, but can occasionally be severe enough to require hospitalisation. The longer the illness lasts (and the more severe it is) the more likely the untreated patient is to develop AIDS within five years.