There is a short period of time between exposure to HIV and the ability for tests to detect HIV or its antibodies. This is called the window period and is generally six weeks after infection. In some cases, the window period can be up to 12 weeks after infection.
A negative HIV test result means that you have either:

  • not been infected with HIV or
  • have been infected with HIV recently (within the last 6 weeks), but your body has not yet produced antibodies to fight the infection

In cases where your body has not yet produced antibodies, you are most likely in the window period. You can be tested again in 6 weeks time.