A white blood cell count is generally part of a complete blood count when someone is either receiving a physical or has an undiagnosed condition that is creating problems.  The white blood cells are created in bone marrow, the fatty substance inside the bones.  They are the body’s protectors against disease and their production is increased when the immune system detects a health threat to the body.

Normally, the number of white blood cells will increase while the threat is being handled and will reduce as the health threat reduces.  If there is a higher or lower than normal white blood count, this can require additional tests to determine the actual cause.   Smoking can increase the number of white blood cells because the body may perceive the smoke as a threat and release more white blood cells.

Generally the white blood cell count test is ordered when the patient has:
Fever

Chills

Headaches

Other forms of illness

NORMAL RESULTS

The white blood cell count is measured in cells per microliter (one millionth of a liter).  The normal range is normally between 4,500 to 10,000 cells/mcL.

HIGHER THAN NORMAL LEVELS

A higher than normal white blood cell count is called leukocytosis.  (Leuko = white, cytosis=higher than normal amount of cells)  Leukocytosis can sometimes indicate:
Bacterial infection

Virus
Inflammation in the body

Leukemia

Recent heart problems or other trauma
Mental or physical stress

Allergies
Asthma

LOWER THAN NORMAL LEVELS

A lower than normal white blood cell count is called leukopenia.  (Leuko=white, penia=poverty) Leukopenia can sometimes indicate:
Bone marrow disorders
Lymphoma (Cancer of the lymph nodes)
Autoimmune disorders
HIV