The CD4 count is like a snapshot of how well your immune system is functioning. CD4
cells (also known as CD4+ T cells) are white blood cells that fight infection. The
more you have, the better. These are the cells that HIV kills. As HIV infection
progresses, the number of these cells declines. When the CD4 count drops below 200
due to advanced HIV disease, a person is diagnosed with AIDS. A normal range for CD4
cells is between 600 and 1,500.
The higher your CD4 count, the better.
The same test that measures your CD4 count usually includes a CD8 cell count, too.
CD8 cells (also known as CD8+ T cells) are another type of white blood cell that
seek out and destroy cells infected with viruses, including HIV-infected cells.
