What are CD4 cells, CD4:CD8 ratio and CD4 percentage?
CD4 cells are a type of lymphocyte (white blood cell). They are an important part of the immune system. CD4 cells are sometimes called T-cells.
There are two main types of T-cells. T4 cells, also called CD4+, are “helper” cells. They lead the attack against infections. T8 cells, (CD8+), are “suppressor” cells that end the immune response. CD8+ cells can also be “killer” cells that kill cancer cells and cells infected with a virus.
The normal ranges for CD4 and CD8 counts varies depending on the lab and test, but for an HIV negative person a normal CD4 count is in the range 460 to 1600. This is an approximate. Anywhere in this ranges is fine. an HIV negative person with a normal CD4 count of 1200 is not more health than someone whose normal count is 600. A normal CD8 range is from 150 to 1000.
The ratio of CD4 cells to CD8 cells is often reported. This is calculated by dividing the CD4 value by the CD8 value. In HIV negative people, this ratio is between 0.9 and 1.9, meaning that there are about 1-2 CD4 cells for every CD8 cell.
In HIV positive people not on treatment, this ratio drops over time until there are more CD8 cells than CD4 cells (i.e. the ratio drops to less than 1.0).
Because the CD4 counts can vary from day to day and hour to hour, if you ever get an unexpectedly high or low CD4 count your CD4% (CD4 percentage) will indicate if this is a real change. The percentage refers to total lymphocytes.
If your test reports CD4% = 34%, that means that 34% of your lymphocytes were CD4 cells.
This percentage is more stable than the number of CD4 cells. The normal range for HIV-negative adults is about 40% (range 30% to 60%).
Information on this website is provided by treatment advocates and offered as a guide only. Decisions about your treatment should always be taken in consultation with your doctor.