White blood cell (leukocyte)
White blood cells are made in the bone marrow and protect the body against infection. If an infection develops, white blood cells attack and destroy the bacteria, virus, or other organism causing it.
White blood cells are bigger than red blood cells and normally are fewer in number. When a person has a bacterial infection, the number of white cells can increase dramatically.
The white blood cell count shows the number of white blood cells in a sample of blood. A normal white blood cell count is between 5,000 and 10,000 cells per cubic millimeter. The number of white blood cells is sometimes used to identify an infection or to monitor the body's response to treatment.
There are five types of white blood cells: lymphocytes, monocytes, neutrophils, basophils, and eosinophils.
| Author | Jeannette Curtis |
| Author | Caroline Rea, RN, BS, MS |
| Editor | Kathleen M. Ariss, MS |
| Editor | Susan Van Houten, RN, BSN, MBA |
| Associate Editor | Tracy Landauer |
| Associate Editor | Pat Truman |
| Primary Medical Reviewer | Patrice Burgess, MD - Family Medicine |
| Primary Medical Reviewer | Adam Husney, MD - Family Medicine |
| Primary Medical Reviewer | Kathleen Romito, MD - Family Medicine |
| Last Updated | May 25, 2007 |
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