Monitoring your CD4 or T-cell count is critical in managing HIV and understanding how it is affecting you and your body. CD4 cells are a critical part of your immune system. They are infected and destroyed by HIV.

Sometimes, they can be depleted to such dangerous levels that they are unable to play their part in helping your immune system work properly. If this happens, you could be at risk of developing AIDS or AIDS related illnesses.

CD4 counts used to be the only way to understand how HIV was affecting your immune system. The CD4 count is a measure of the damage already done. The viral load is a measure of the risk of future damage.

A general guide to CD4 test results is:

• 500 to 1,350 CD4 is the ‘normal’ range for adults;
• more than 500 CD4 indicates little or no immune system damage;
• between 500 and 250 CD4 cells indicates some damage but it is unlikely you will be at risk of major opportunistic infections; and
• less than 250 CD4 indicates more serious immune system damage and suggests that you could be at risk of serious opportunistic illnesses.
• CD4 percentages measure the proportion of CD4 cells against other types of white blood cells. The percentage is more an indication of the stability of CD4 count over time, rather than the actual CD4 count. The percentage can indicate how stable the CD4 count is and may vary less than an actual CD4 count. For example, a person with a CD4 count of 350 at 23% could indicate more stability and less chance of disease progression than a person with a CD4 count of 500 at 15%. Together with viral load and the CD4 count, it’s another result that is used by your doctor to assist in determining your optimal treatment strategies.