The CD4 count measures the number of CD4 cells there are in a unit of the individual's blood.
CD4 cells, also known as T-cells, are an important part of the immune system.
People with AIDS have fewer CD4 cells than healthy people have. Different people with AIDS may have different numbers of CD4 cells.
Those with higher CD4 counts usually feel better and are less likely to get opportunistic infections.
This test is used to monitor the effectiveness of a course of treatment.
If the medications raise the CD4 count, that means they are working.
Regardless of the CD4 count, a person who has been infected with HIV remains infected, which means that the person can pass on the virus to others. People with high CD4 counts may appear to be healthy, and may feel pretty good, but they still can pass the HIV virus to others.