Elevated WBC or leukocytosis may be caused by several conditions including bacterial infection, inflammation, leukemia, lymphoma, trauma, use of certain drugs (steroids, antiseizure medications), myeloproliferative
disorders of the bone marrow (chronic myelogenous leukemia, polycythemia vera, myelofibrosis, essential thrombocythemia), inflammatory bowel disorders (Crohn’s disease, ulcerative colitis), burns or stress (physical or emotional).