Medical Definition of Neutrophil. Neutrophil: A type of white blood cell, a granulocyte that is filled with microscopic granules, little sacs containing enzymes that digest microorganisms. Also known as polymorphonuclear leukocyte or poly.
Definition of Neutropenia. Neutropenia: Not enough neutrophils, neutrophils being a type of white blood cell (specifically a form of granulocyte) filled with neutrally-staining granules, tiny sacs of enzymes that help the cell to kill and digest microorganisms it has engulfed by phagocytosis.
Neutropenia is classified as mild, moderate, or severe, based on the ANC. Mild neutropenia is present when the ANC is 1000-1500 cells/ÂµL, moderate neutropenia is present with an ANC of 500-1000/ÂµL, and severe neutropenia refers to an ANC lower than 500 cells/ÂµL. The risk of bacterial infection is related to both the severity and duration of the neutropenia.