The Window Period and Testing

As the HIV antibodies will appear only after 3 weeks to 6 months of infection, some infected people will test negative because their body hasn’t got around to producing antibodies. This period of time is referred to as the "window period". To ensure that one does not take the antibody test during the "window period"; one should wait at least 12 weeks (3 months) from the time of possible exposure before taking the test. Anybody who tests negative but thinks that they have been exposed to the virus should consider having another test six months later.