HIV infection is normally detected using an HIV antibody test. This test looks for the antibodies the immune system produces to fight HIV infection. It is very accurate.

The overwhelming majority of people infected with HIV will produce antibodies within 45 days of infection. Some people produce antibodies sooner, and in a very small number of people it can take six months, or even longer, for antibodies to appear after infection.

The HIV antibody test is not an ‘AIDS test'. There is no such thing.

Tests can also be used to look for HIV itself (an antigen test) or parts of its genetic material (a PCR – polymerase chain reaction – test), often called a viral load test. Viral load testing is covered in a lot more detail in the section Key tests to monitor HIV - CD4 and viral load.