[Clarification of neutropenia].

Detection of neutropenia depends on the white cell count and the differential count, both of which involve considerable error. Pathogenetically, neutropenia can be attributed one of the following mechanisms: insufficient (or inefficient) formation, enhanced destruction or utilization, or--rarely--shift to the marginal pool. Isolated neutropenia should be distinguished from neutropenia combined with anemia and/or thrombocytopenia. The latter is usually due to bone marrow failure, whereas the former depends on peripheral mechanisms. Drug induced neutropenia may appear either as unforeseen acute agranulocytosis (aminophenazone type), depending on preceding sensitization, or as a slowly developing, dose-dependent cytopenia. Gradually developing neutropenia is an early stage of a general disease (collagen diseases, leukemia and other neoplasias, infections).