- Last Update On : 2013-03-10
The number of white blood cells per microliter is part of the routine complete blood count (CBC). Leukocytosis is defined as a WBC greater than 11, 000/uL and may be due to a reactive or neoplastic increase in neutrophils, lymphocytes, or, less commonly, monocytes or eosinophils. Leukopenia is defined as a WBC less than 4,000/uL and is usually due to neutropenia.
Reference range is 4000 to11000 cells/uL in adults. White blood cell counts <1000 and >50,000 are considered critical values.
Specimen requirement is one lavender top (EDTA) tube.