WHITE BLOOD CELL COUNT

The WBC count determines the number of leuko-
cytes per cubic millimeter of whole blood. The
counting is performed very rapidly by electronic
devices. The WBC may be performed as part of a
CBC, alone, or with differential WBC count. An
elevated WBC count is termed leukocytosis; a
decreased count, leukopenia. In addition to the
normal physiological variations in WBC count,
many pathological problems may result in an abnor-
mal WBC count (see Table 1–2).
If the WBC count is low, a buffy coat smear can be
performed to identify leukemia or solid tumor cells
in the blood. An alteration in total WBC count indi-
cates the degree of response to a pathological process
but is not specifically diagnostic for any one disor-
der.A more complete evaluation is obtained through
the differential WBC count.
INDICATIONS FOR A WHITE BLOOD CELL COUNT
- Routine screening as part of a CBC
- Suspected inflammatory or infectious process.
- Suspected leukemia, autoimmune disorder, or
allergy
- Suspected bone marrow depression
Monitoring response to stress, malnutri-
ion, and therapy for infectious or malignant
processes