An HIV-negative result does not mean that you do not have HIV. That is because of the window period, the time between HIV exposure and when a test may detect HIV in your body. If you get an HIV test after a potential HIV exposure and the result is negative, get tested again after the window period for the test you took. If you do the test again after the window period, have no possible HIV exposure during that time, and the result is negative, you do not have HIV.