Treatment training manual

1.13 Use of CD4 count for starting therapy (ART)

Until 2015, the CD4 count was used to decide when to start ART.

Although some guidelines still use the CD4 count at a criteria for starting ART, the main use of CD4 counts is to know how much HIV has damaged your immune system.

At what CD4 count should someone start ARV treatment?

  • WHO, European, UK and US guidelines recommend people can start ART at any CD4 count. This includes when the CD4 count is higher than 500.
  • A few guidelines still only recommend ART after the CD4 count has dropped below 500 or even 350.
  • If there is limited access to treatment, some guidelines recommend that people with the lowest CD4 count have a more urgent need of ART

Large studies have shown that ART reduces the risk of HIV related infections even when the CD4 count is higher than 500.

Several years ago, both UK and US treatment guidelines recommended starting at lower levels (at 500, 350 and even 200). This was because of the higher risk of side effects with early HIV drugs.

Modern ART is now much safer. More recently approved drugs have fewer risks of side effects. Modern combinations also require fewer pills and numbers of daily doses and this makes taking treatment easier.

In practice, many people who start ART at much lower CD4 counts because they are diagnosed later in infection. ART will will still work very well.

Last updated: 1 January 2016.