Your CD4 cell count gives an impression of the health of your immune system.

Monitoring your CD4 cell count can help you and your doctor decide when you need to start HIV treatment.

Viral load is the term used to describe the amount of HIV in your blood.

CD4 cell counts and viral load can vary naturally - you should look at trends, not single results.

The aim of anti-HIV treatment for people who have never taken HIV drugs before is a viral load below 50 copies, this is usually called an undetectable viral load.