The normal white blood count is between 3.5 billion and 10.5 billion cells per liter, according to Mayo Clinic. A low white cell count indicates an autoimmune disease, while a high count indicates inflammation or infection.
A doctor often orders the white blood count as a part of a complete blood count. The doctor sometimes orders the test to review the patient's overall health, according to Mayo Clinic. In other cases, the doctor orders the test to diagnose a certain condition, monitor a medical problem or check the health condition of a patient taking medication that affects blood cell counts. The test involves drawing blood from a vein, normally inside the elbow, for laboratory analysis.