Toxic granulation



The term “toxic granulation” describes the presence of large darkly-staining granules in the cytoplasm of circulating neutrophils – usually in the context of other reactive features

Images of toxic granulation

Two neutrophils containing very obvious coarse basophilic granules - this appearance indicates an increase in the number of primary granules (which are coarser than normal secondary granules). Both these examples are from G-CSF treatment, but similar changes may arise from a range of inflammatory processes.


In non-activated cells, the secondary (specific) granules (that contain complement activators and collagenases) are the most numerous granule type. Toxic granulation is believed to represent an increase of the number of primary (azurophilic) granules which develops in response to an inflammatory stimulus. These granules contain myeloperoxidase and facilitate killing of bacteria.


  • Toxic granulation occurs during inflammation or in response to G-CSF treatment - look for other activation features including Döhle bodies and/or vacuoles
  • Where granulation resembles toxic granulation but looks atypical or involves monocytes and lymphocytes, consider congenital causes