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- What is happening inside me?
There are two blood tests that we get done regularly when we go to the HIV clinic. These give a good indication of how well our immune systems are coping with HIV.
Knowing what’s going on can help us make decisions about things like lifestyle and treatment. It can also help to make everything seem a bit less mysterious.
CD4 cell count
Knowing how many CD4 or T-cells we’ve got in a sample of our blood is a guide to how healthy our immune system is.
Normal CD4 count
A healthy adult man has a CD4 count of between 400 to 1600 CD4 cells per cubic millimetre of blood.
Damaged immune system
A CD4 count of between 200 and 500 indicates that some damage has been done to our immune system. But it doesn’t necessarily mean we’re at high risk of getting seriously ill.
Diseases associated with late stage HIV infection don’t usually start to appear until our CD4 count falls to 200 or below. Treatment can stop this happening.
Viral load test
Our viral load is the amount of HIV present in our blood. Without treatment, HIV constantly multiplies and our viral load increases. The more HIV we have, the faster our CD4 count falls.
The test for viral load measures how many particles of HIV are circulating in our blood. The results are given as the number of copies of HIV per millimetre of blood; for example 200 copies/ml.
What the figures mean
The higher our viral load is, the more likely our disease is to get worse and the more infectious we are. A viral load above 100,000 copies/ml is considered high. A viral load below 10,000 copies/ml is considered low.
Our viral loads can fluctuate a lot if we’re not taking HIV treatment. So looking at the trend over a number of months is more useful than comparing two test results.
When viral loads are very low – say 50 copies/ml or lower – the test cannot reliably detect HIV. We will then be told our viral load is ‘undetectable’. This doesn’t mean that HIV is no longer there, though; just that the test cannot detect it.
Treatment and viral load
The goal of HIV treatment is to reduce our viral load to undetectable levels so that HIV doesn’t cause much damage to our immune systems. This allows our immune systems to recover.
Reduced viral load also means we are less infectious, so it’s more difficult to pass the virus on to someone else.
How viral loads relate to CD4 counts
A high viral load will usually mean a low CD4 count.
