Leukocytosis is a condition characterized by an elevated number of white cells in the blood. Leukocytosis is a condition that affects all types of white blood cells. Other illnesses, such as neutrophilia, lymphocytosis, and granulocytosis, target specific types of white blood cells. Normal white blood cell counts are 4,300-10,800 white blood cells per microliter. Leukocyte or white blood cell levels are considered elevated when they are greater than 11,000 per microliter. The increased number of leukocytes can occur abnormally as a result of an infection, cancer , or drug intake; however, leukocytosis can occur normally after eating a large meal or experiencing stress (caption above: T his blood is from a patient with a white blood cell count of more than 68,000 per microliter, more than six times the normal number).