Infocenter

Commonly-used HIV tests detect antibodies produced by the immune system in response to HIV infection.  Although HIV antibody tests are very sensitive, there is a ‘window period’ of 3 to 12 weeks, which is the period between infection with HIV and the appearance of detectable antibodies to the virus.  During this ‘window period’ of early infection a person is at their most infectious.  Therefore it is generally recommended to wait three months after possible exposure before being tested for HIV.  This period may be longer if less sensitive tests are used.¹

More modern tests like Determine® HIV-1/2 Ag/Ab Combo simultaneously detect antibodies against HIV-1 and HIV-2 together with HIV p24 antigen.  The p24 antigen (Ag) is produced during the first few weeks of HIV infection and is detectable before HIV antibodies are produced, making it an ideal marker for the identification of acute HIV infection. Due to separate signals for HIV Ag and anti-HIV Ab, Determine® HIV-1/2 Ag/Ab Combo provides determination and differentiation of the infection phase.

By understanding their HIV status, individuals are able to gain early access to specific treatment, care and counselling, prevent transmission, and plan for the future.