Persons with leukemia may have elevated counts greater than 11,000 white blood cells per cubic millimeter of blood, many of which are abnormal and not fully-developed. The 'normal' range in healthy individuals is 4,500 to 10,000, according to about.com.
While white blood cell count does not indicate a specific disease, it is useful to physicians in monitoring the course of leukemia and other diseases.
A higher than typical count is known as 'leukocytosis,' and associated with allergies,bacterial infection, inflammatory disease, malignancy and trauma. Counts below 4,000 indicate 'leukopenia,' most commonly the result of drug allergies, immune system disorders, viral infection or chemotherapy or radiation therapy side effects.