How long after a possible exposure should I wait to get tested for HIV?

The tests commonly used to detect HIV infection are actually looking for antibodies produced by your immune system when you are exposed to HIV. Most people will develop detectable antibodies within two to eight weeks (the average is 25 days). Ninety-seven percent will develop antibodies in the first three months following the time of their infection. In very rare cases, it can take up to six months to develop antibodies to HIV.