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 a condition in which the number of neutrophils (a type of white blood cell) in the bloodstream is decreased, affecting the body's ability to fight off infections. Neutropenia is defined as an absolute neutrophil count (ANC) of less than 1500 per microliter (1500/microL); severe neutropenia is defined as an ANC of less than 500/microL. Neutropenia may be caused by or associated with numerous medical conditions including congenital disorders of the bone marrow, cancer chemotherapy, infections, certain medications (drug-induced neutropenia), and autoimmune disorders.