noun, plural: leukocytoses
An abnormal increase in white blood cell count in the blood.
Leukocytosis is not a disease but a laboratory finding that indicates possible infection since increase in the number of white blood cells could mean heightened immune activity against pathogens.
The normal adult human leukocyte count in the peripheral blood is 4.4-10.8 x 10 9/L. Thus, a white blood count of 11.0 x 10 9/L or more suggests leukocytosis.
Word origin: leukocyte + Latin –osis, from Greek –osis (an increase, a condition).
Related forms: leukocytotic (adjective)
Compare: leukopenia, erythrocytosis.
See also: neutrophilia, lymphocytosis, monocytosis, eosinophilia, basophilia.