HIV replicates rapidly when it first enters your body. While the exact time frames are unique to the individual, the virus usually peaks within the first month of infection. During this time viral loads are sky high, and the risk of passing on HIV during unprotected sex is extremely high.

Evidence of HIV can be detected by some tests as early as 2 weeks after exposure, but it may take up to 3 months. Everyone responds differently to the virus.

Most HIV tests detect antibodies. Antibodies are your immune system’s response to the virus, not the virus itself. Some tests for HIV can also detect antigens, which are proteins attached to the virus itself - but these tests are much less common.

Because of the delay in detectability, if you think you have been exposed to HIV, and you test negative the first time, you will need to test again after 3 months to confirm the result.

The ‘window period’ is the time between when you are first exposed to HIV to when the virus can be picked up in a test. Even though HIV can be picked up as early as 2 weeks after exposure, the general rule of thumb for the window period is between 4 and 12 weeks.

There is always a chance that you may schedule a test for HIV before any sign of the virus can be picked up. Because of this, if you test negative at first, you need to test again after the window period is over (usually 12 weeks).

Provided you haven’t been at risk of HIV in the meantime, testing negative after the window period has passed means you are very unlikely to have HIV. Find out all more about your HIV risk here.

If you test positive for HIV, you will need to test again to confirm the result. It is standard practice to confirm positive results with further tests, to make sure people are not told they have HIV when they do not. 

If your test result is positive you will be immediately referred to support, while further testing is carried out. Testing positive for HIV initially is not the same as being diagnosed with HIV. That comes, or not, once follow-up testing is complete.

HIV testing is undertaken by trained professionals. They are bound by privacy laws to keep your test results confidential.