What does a CD4 measure?

A CD4 test measures the number of CD4 cells, a type of white blood cell that plays a crucial role in the immune system, particularly in fighting infections. It is commonly used to monitor the immune status of individuals with HIV, as HIV primarily targets and destroys CD4 cells. Lower CD4 counts indicate a weakened immune system and a higher risk of opportunistic infections. Regular monitoring of CD4 levels helps guide treatment decisions for HIV patients.