Question
Is my CD4% results is more stable than CD4 count?
24 February 2012. Related: All topics, CD4 and viral load, Starting treatment.
Hi, I have been positive since 1999, and was diagnosed in 2004. During this period my viral load has been below 1000, and as low as 50. Last month, it was 150. My CD4 was 505 in 2004, but it has gone up and down and gotten as low as 191 last month. My CD4% has been between 31% to 41%.
My doctor has wanted me to start medication for the last two years but I have been very resistant for personal reasons, but also the fact that other specialists often write that the CD% is the more stable number than CD4 count and my CD4% has been very stable. What do you think?
My last test, a month ago showed, CD4 191, CD4% 35, viral load 150. Do you have any insight as to why the numbers differ like this?
Answer
I’m sorry it has taken a few days to get back to you – we have had a busy time here recently.
In general, the CD4 count (sometimes called the ‘absolute’ CD4 count) is a pretty good marker, and certainly the most widely used test for decided when to start treatment. So in all studies, it is very predictive of risk of other health complications.
This risk is dramatically increased when the CD4 count drops below 200. So guideline for many years used this as the cut-off to start treatment. More recently, with easier treatment, this has raised in most countries to 350, and in some to 500.
These are all population-based recommendations though. However, they are based on enough solid data that this makes your doctor worried about your decision to stay off treatment. Probably your doctor is right.
The disconnect between your CD4 count which is low and your percentage which is high, is reported in only a minority of people. It is not very well understood. If your CD4 had had always been low – for example, if it had always been around 200-300, this might be a reason to consider staying off treatment.
The range of CD4 counts in HIV negative people is pretty wide. About 95% of people will be between 400 and 1600. As far as I know, where you are in that range doesn’t directly relate to the health of these HIV negative people. Some people normal levels are high, some are low, but their immune systems all work pretty much the same. They would all expect their CD4 percentages to be normal (perhaps in the 35-50% range). A few people with have ‘normal’ counts that are even lower, and if they became HIV positive, based on the guidelines, they would be started on treatment, even though the HIV had not reduced their normal levels.
However, because your CD4 count was as high as 500 and has slowly dropped over the years, it indicates HIV is likely to be damaging your immune system. Even though your CD4% is still high, your doctor is probably giving you good advice in the recommendation to start treatment.
This old publication (from 1997) includes information about the ranges of CD4 counts in relation to percentages. Although it is quite technical, just might find it interesting as background reading for how wide these ranges can be. Please click here to down the file.
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