There are five major types of white blood cells, each with its own particular job, but all participate in the immune response. Some white cells are produced in the bone marrow. They are responsible for producing antibodies which look for and destroy specific foreign antigens White cells have a much shorter life than red cells, and stress can shorten that life span to as little as 2-3 hours. An elevated WBC or white blood cell count can be an indicator of infection or of some forms of cancer. Normal WBC is from 4,000 to 10,000 per microliter of blood.
Normal values vary with sex, age and weight.
A count below 50,000 can cause spontaneous bleeding, and much lower than 50,000 can become life threatening. The blood sample is placed in a glass tube and placed in a rack. A timer records how fast the red cells settle to the bottom of the tube. The white cells collect in the middle, and the clear, yellow plasma on top. ESR or SED rate is a measure of inflammation and is a frequent test for autoimmune disorders like arthritis Normal rates are from 0 to 20 and gradually increase with old age.