CD4 count

A CD4 count measures the number of CD4 cells (a type of white blood cell) in a cubic millimeter of blood. These cells are crucial for the immune system’s ability to fight infections. A healthy person typically has a CD4 count between 500 and 1,600. In HIV-positive individuals, the CD4 count indicates immune system strength; lower counts suggest greater immune deficiency and higher risk for infections or illnesses. Monitoring CD4 counts helps healthcare providers assess disease progression and determine treatment effectiveness.