The normal range of white blood cells is 4,500 to 10,000 per microliter of blood, according to MedlinePlus. Because labs may vary slightly in their normal ranges, it is advisable to consult a physician regarding WBC test results.
White blood cells are cells that help fight infection, as reported by MedlinePlus. The number of these cells is measured by blood tests. These tests reveal the total count and various types white blood cells. Low white blood cell counts can indicate bone problems, liver disease or viral illnesses, while high counts may signify bacterial infections, anemia, or severe physical or mental stress. Cigarette smoking, and severe mental or physical stress may also cause elevated white blood cell counts. Potential causes of a low white blood cell count include bone marrow problems, cancer treatment, autoimmune disorders, and diseases involving the liver or spleen.
White blood cells can be broken into five different categories: basophils, eosinophils, lymphocytes, monocytes and neutrophils. All of these types work together to fight off infections in the body, according to MedlinePlus. Lymphocytes are also referred to as T cells and B cells.