Granulocytes are a type of white blood cell that is made of small granules, which contain proteins. The types of these cells are neutrophils, eosinophils, and basophils.
Granulocytes help the body fight bacterial infections. The number of granulocytes in the body goes up when there is a serious infection. People with lower numbers of granulocytes are more likely to get bad infections more often.
Granulocytes are counted as part of a white blood cell differential test.
Berliner N. Leukocytosis and leukopenia. In: Goldman L, Schafer AI, eds. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 170.