A normal CD4 count ranges from 500 to 1,500 cells per cubic millimeter of blood, states WebMD. Any value below this range indicates a weak immune system.
CD4 count varies from person to person and is affected by illness, infections, stress, smoking and recent vaccinations. It represents the number of cells in a cubic millimeter of blood. CD4 count can also be represented as a percentage, and the normal range is between 30 and 60 percent. A CD4 count of less than 14 percent or 200 cells per cubic millimeter indicates serious damage of the immune system or the onset of Aids, states The Body, a website for HIV/AIDS resources.