Pappenheimer bodies are abnormal granules of iron found inside red blood cells on routine blood stain. They are a type of inclusion body formed by phagosomes that have engulfed excessive amounts of iron. They appear as dense, blue-purple granules within the red blood cell and there are usually only one or two, located in the cell periphery. They are seen in diseases such as sideroblastic anemia, hemolytic anemia, and sickle cell disease. They can interfere with platelet counts when the analysis is performed by electro-optical counters.
Pappenheimer bodies are visible with a Wright and/or Giemsa stain. Confirmation of non-heme iron in the granules is made with a Perls' Prussian blue stain.