The HIV window period is a critical concept for anyone who has had a high-risk exposure and is worried about HIV infection. Simply put, the window period is the time between when you are infected with HIV and when a test can detect the virus or its markers (antibodies, antigens) in your body. During this time, you may have HIV in your body and be able to transmit it to others, but your test result will be negative — this is called a “false negative.”