A leukocyte count is a count of the number of white blood cells in a person’s blood. It is also called a white blood cell (WBC) count. The count is determined through a blood test which is usually performed as part of a complete blood count (CBC). The blood test can determine if a person’s leukocyte count is lower or higher than normal. A leukocyte count that is low is called leukopenia, whereas a count that is high is referred to as leukocytosis.
Leukocytes are an important part of the body’s system, as they are cells that help fight off infection and disease. There are many types of leukocytes including basophils, lymphocytes and neutrophils. Others include band cells, eosinophils and monocytes. Generally, there is a normal count of leukocytes that should be found in a person. When that person has an infection, though, the body might produce more leukocytes to defend itself.
A normal leukocyte count depends on the medical institution or laboratory that analyzes the results of the blood test. Usually, a normal count might range anywhere between 4,500 and 10,000 leukocytes per microliter. A count that is any lower or higher is considered abnormal and might be caused by any number of factors. Leukopenia, for example, might be caused by autoimmune disorders or radiation. Leukocytosis, on the other hand, might come about as a result of stress or tissue damage.
The blood test itself is generally a straight-forward procedure. The person taking the blood sample uses a needle to draw blood from a vein. Usually, the test site is on the arm at the inner elbow, although there are other areas that might be used instead. Before the needle is inserted, an elastic band is wrapped above the test site to ensure that enough blood is available. For young children, a leukocyte count test might be a bit different; instead of using a needle, the person performing the test might pierce the skin with a lancet.
After the blood is drawn, it is then collected into a tube or slide. While having their blood drawn, some people might feel pain while others might only feel the prick of the needle. In addition, sometimes the area around the test site might throb after the test is done. Though a blood test is not considered a dangerous procedure, a person should be aware of the associated risks. These risks include fainting, hematoma or infection.