Leukocytosis 780373 214954033 2008-05-26T01:43:36Z PipepBot 4984067 robot Adding: [[it:Leucocitosi]] {{DiseaseDisorder infobox | Name = Leukocytosis | ICD10 = {{ICD10|D|72|8|d|70}} | ICD9 = {{ICD9|288.3}}, {{ICD9|288.6x}} | Image = | Caption = | ICDO = | OMIM = | DiseasesDB = 33024 | MedlinePlus = | eMedicineSubj = | eMedicineTopic = | MeshID = D007964 | }} '''Leukocytosis''' is a raised white blood cell count (the [[leukocyte]] count) above the normal range. Although it may be a sign of illness, leukocytosis in-and-of itself is not a disorder, nor is it a disease. It is simply a laboratory finding. A leukocyte count above 25 to 30 x 10<sup>9</sup>/[[litre|L]] is termed a ''[[leukemoid reaction]]'', which is the reaction of a healthy bone marrow to extreme stress, trauma, or infection. (It is different from [[leukemia]] and from [[leukoerythroblastosis]], in which immature blood cells are present in peripheral blood.) ==Leukocyte counts== The normal adult human leukocyte count in peripheral [[blood]] is 4.4-10.8 x 10<sup>9</sup>/[[litre|L]]. A white blood count of 11.0 x 10<sup>9</sup>/[[litre|L]] or more suggests leukocytosis. ==Causes== Leukocytosis is very common in acutely ill patients. It occurs in response to a wide variety of conditions, including viral, bacterial, fungal, or parasitic infection, cancer, hemorrhage, and exposure to certain medications or chemicals including steroids. Leukocytosis can also be the first indication of [[neoplastic]] growth of leukocytes. For lung diseases such as pneumonia and tuberculosis, WBC count is very important for the diagnosis of the disease, as leukocytosis is usually present. The mechanism that causes leukocytosis can be of several forms: an increased release of leukocytes from [[bone marrow]] storage pools, decreased margination of leukocytes onto vessel walls, decreased [[leukocyte extravasation|extravasation]] of leukocytes from the vessels into tissues, or an increase in number of precursor cells in the marrow. ==Classification== Leukocytosis can be subcategorized by the type of white blood cell that is increased in number. Leukocytosis in which [[neutrophil]] count is elevated is [[neutrophilia]]; leukocytosis in which [[lymphocyte]] count is elevated is [[lymphocytosis]]; leukocytosis in which [[monocyte]] count is elevated is [[monocytosis]]; and leukocytosis in which [[eosinophil]] count is elevated is [[eosinophilia]]. [[Category:Hematology]] {{med-sign-stub}} {{Hematology}} [[de:Leukozytose]] [[es:Leucocitosis]] [[fr:Leucocytose]] [[it:Leucocitosi]] [[pl:Leukocytoza]] [[pt:Leucocitose]] [[ru:Лейкоцитоз]]