Looking at CD4 and viral load together
If you're not currently taking HIV treatment
If you’re not currently taking HIV treatment, your viral load and CD4 cell count can help predict your risk of becoming ill because of HIV in the future.
Among people with the same CD4 cell counts, research has shown that those with a higher viral load tend to develop symptoms more quickly than those with a lower viral load.
In addition, among people with the same viral load, those with lower CD4 cell counts tend to become ill more quickly.
Deciding when to start treatment
Your viral load and CD4 cell count can help you decide if you need to start taking anti-HIV treatment.
At the moment, doctors put more emphasis on the level of your CD4 cell count, and it is recommended that once your CD4 cell count falls below 350, you should start treatment as soon as you are ready. It is also recommended that if your CD4 cell count is below 250 you should start treatment straight away. This is because your risk of illness is greater if when your CD4 cell count is below 200.
At higher CD4 cell counts, your decision will depend on a combination of the level of your viral load, the speed at which your CD4 cell count is falling, any symptoms you may have, the presence of other infections such as hepatitis C, risk of illnesses such as heart and kidney disease and your wishes.
The question of when to start HIV treatment is looked at in a lot more detail in the section HIV treatment.
Monitoring the effectiveness of treatment
Effective HIV treatment results in a fall in your viral load. Within about four weeks of starting HIV treatment, your doctor should test your viral load to see how much it has fallen.
The aim of treatment in people who have never taken anti-HIV drugs before is to get viral load to undetectable levels (below 40 or 50, depending on which test your clinic is using) within 24 weeks. If your viral load never becomes undetectable, or increases to become detectable in two consecutive tests after it has been undetecrtable then your doctor should talk to you about changing your HIV treatment.
As your viral load falls, your CD4 cell count should begin to slowly increase.