An abnormal total white blood cell count is any count below 4,500 or above 10,000 white blood cells per microliter of blood, states MedlinePlus. If a patient has an abnormal white blood cell count, further testing may be done.
White blood cells are important immune cells that help the human body fight off pathogens, according to MedlinePlus. There are five different types of white blood cells: basophils, eosinophils, lymphocytes, monocytes and neutrophils. Low white blood cell counts may indicate a range of disorders, including cancer, bone marrow deficiency and autoimmune disease. High white blood cell counts may indicate issues including anemia, smoking and certain cancers.