Siderocytes are normal adult RBC with stainable iron. The number of siderocytes are increased following splenectomy as the spleen is the normal site for removal of residual iron from the retic. Residual iron granules are called siderotic granules and measure from 0.5 to 1.0 microns in diameter. They are preferentially located near the edge of the cell. They will stain blue with Prussian blue but do not stain with the Wright's stain.
Pappenheimer bodies are iron granules in mitochondria.
As a result of the protein of the mitochondria they stain positive with Prussian Blue and Wright's stain. Basophilic stippling is often confused as siderotic granules and Pappenheimer bodies. These are ribosomes scattered in cell and stain positive with Wright's and negative with Prussian Blue. Sideroblasts are normal nucleated RBC with stainable iron. The iron granules are small and randomly scattered through the cytoplasm.