Finding out about tests

There are two key blood tests used to assess the impact HIV is having on your immune system. These are called CD4 cell counts and viral-load tests.

A CD4 cell count gives a rough idea of how healthy your immune system is, and the viral-load test gives an indication of how active HIV is in your body. The more active HIV is, the lower your CD4 cell count becomes, and the greater your risk of becoming unwell because of HIV. Find out more about these tests by reading the section Key tests to monitor HIV.