A normal white blood cell count for any person ranges between 3.5 to 10.5 billion per liter, as reported by Mayo Clinic. A count that falls above or below the normal range requires follow-up with a physician, as it can indicate a serious underlying health issue.
Various medications result in a white blood cell count outside the normal range, according to Mayo Clinic. A count below 3.5 billion per liter — leukopenia — is a possible indicator of cancer, an autoimmune disease or an issue with bone marrow. An infection — or inflammation, in general can cause a count above 10.5 billion per liter. An abnormally high count can also be the result of issues with the immune system or bone marrow.