The tests commonly used to determine HIV infection actually look for antibodies produced by the body to fight HIV. According to the Centers for Disease Control and Prevention (CDC), most people will develop detectable antibodies within 3 months after infection. In rare cases, it can take up to six months. Therefore, the CDC recommends testing at 6 months after the last possible exposure. (unprotected vaginal, anal or oral sex or sharing injecting drug needles). It would be extremely rare to take longer than six months to develop detectable antibodies. It is important, during the six months between exposure and the 6-month test, to protect yourself and others from further exposures to HIV. The CDC National AIDS Hotline can provide more information and referrals to testing sites in your area. The hotline can be reached at 1-800-342-2437 (English), 1-800-344-7432 (Spanish), or 1-800-243-7889 (TTY).