DefinitionBy Mayo Clinic staff
A low white blood cell count, or leukopenia, is a decrease in disease-fighting cells (leukocytes) circulating in your blood.
The threshold for a low white blood cell count varies from one medical practice to another. Some healthy people have white cell counts that are lower than what's considered normal. A count lower than 4,000 white blood cells per microliter of blood is generally considered a low white blood cell count. The threshold for a low white blood cell count in children varies with age and sex.
- Kumar V, et al. Robbins and Cotran Pathologic Basis of Disease. 8th ed. Philadelphia, Pa.: Saunders Elsevier; 2010. http://www.mdconsult.com/books/about.do?eid=4-u1.0-B978-1-4377-0792-2..X5001-9--TOP&isbn=978-1-4377-0792-2&about=true&uniqId=376703042-2. Accessed Oct. 27, 2012.
- Kliegman RM, et al. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, Pa.: Saunders Elsevier; 2011. http://www.mdconsult.com/das/book/body/208746819-6/0/1608/0.html. Accessed Oct. 27, 2012.
- Marx JA, et al. Rosen's Emergency Medicine: Concepts and Clinical Practice. 7th ed. Philadelphia, Pa.: Mosby Elsevier; 2010. http://www.mdconsult.com/books/about.do?about=true&eid=4-u1.0-B978-0-323-05472-0..X0001-1--TOP&isbn=978-0-323-05472-0&uniqId=230100505-57. Accessed Oct. 27, 2012