The normal range for a white blood cell count is between 4,500 and 10,000 per microliter of blood, according to MedlinePlus. A high white blood cell count may be due to infection, inflammation, anemia, leukemia and other conditions or certain medications.
White blood cells help fight infection, MedlinePlus explains. A white blood cell count of less than 4,500 per microliter is below normal and increases the risk of infection. A low white blood cell count may occur in patients undergoing drug or radiation treatment for cancer. Other causes for a low white blood cell count include a bone marrow disorder, disease of the liver or spleen, some viral illnesses, such as mononucleosis, and some autoimmune diseases, such as lupus. Severe bacterial infections can also cause a low white blood cell count.
