CD4 and viral loads

There is a lot of terminology relating to HIV and it can be hard to take this in when you are first diagnosed. Two of the most common test results are CD4 Count and Viral Load and these are explained below:

If you’re living with HIV, regular check- ups at your clinic help keep an eye on your health. Some people go more regularly than others, but most people go every 3 – 6 months. People generally go to their HIV clinic to have their blood taken, and then return two weeks later for the results.

Your blood will be monitored for lots of different things. These will include a liver function test, a kidney function test and cholesterol levels. As well as these tests, they‘ll also monitor your CD4 count and viral load.

What do we mean by CD4 count?
CD4 count: is an indication of the strength of the immune system.

In general, the higher your CD4 figure is, then the stronger your immune system is. It is now recommended that anti-viral treatment is offered to you as soon as you are diagnosed HIV Positive. Monitoring your CD4 count will help determine whether the treatment is working properly or not. If your CD4 count has dropped to abnormally low levels due to HIV infection it should start to rise to more normal levels after the treatments begin to take effect.

Because CD4 counts can vary between individuals, a single CD4 count doesn’t tell you very much. Several CD4 counts are needed in order to see if there are any trends.

CD4 counts fluctuate throughout the day. They are generally lower in the morning and increase throughout the day. They are generally higher immediately after exercise and can be affected by diet, stress and other infections. It is important to acknowledge that your CD4 count will have natural variations and these do not mean that you necessarily have a stronger or weaker immune system.

It has been said that a more reliable figure to give an indication of the immune system is the CD4 percentage. Your HIV team will have both your CD4 count and percentage, and if you ask, they will be more than happy to tell you results.

What do we mean by Viral load?
Viral load tells you how much HIV there is per cubic ml of blood; a viral load of 18,000 means that there are 18,000 copies of HIV per cubic ml of blood. In general, the lower this figure the better, because it means there is less HIV in your body. People who have a recent infection will tend to have a higher viral load. A HIV negative person will not have a viral load, as they will not have any HIV in their body.

Viral loads will vary between individuals. In summary a viral load:

  • Between 100,000 to 1 million or more: High
  • Below 10,000 for people not on treatment: Low
  • Below 50: (Known as undetectable): Very low; this is mainly only achieved when taking HIV medication.

The term undetectable viral load can be misleading to some people. Although it is called undetectable, there’s still HIV present in the body. We call it ‘undetectable’ as the computers used to determine the viral load cannot detect HIV if there are below 40 or 50 copies of HIV per cubic ml of blood. Having an undetectable viral load is the aim of treatments and means that:

  • The treatments you are taking is working
  • That HIV is present in very low levels
  • That HIV is causing less damage to the body
  • That the likelihood of passing on HIV is reduced (please see treatment as prevention section for further details).