The White Blood Cell (WBC) Count measures two components: the total number of WBC's (leukocytes), and the differential count. The differential count measures the percentages of each type of leukocyte present. WBC's are composed of granulocytes (neutrophils, eosinophils, and basophils) and non-granulocytes (lymphocytes and monocytes). White blood cells are a major component of the body's immune system. Indications for a WBC count include infectious and inflammatory diseases; leukemia and lymphoma; and bone marrow disorders.
Review Date 1/27/2015
Updated by: Yi-Bin Chen, MD, Leukemia/Bone Marrow Transplant Program, Massachusetts General Hospital, Boston, MA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.