Definition
A siderocyte is a red blood cell containing granules of iron, called siderotic granules, that are visible with special staining. These granules are usually composed of ferritin, a protein that stores iron. Siderocytes indicate an abnormality in iron metabolism or hemoglobin production. They can be found in conditions like sideroblastic anemia or after a splenectomy. Normally, iron is incorporated into hemoglobin within the bone marrow. Their presence in the blood suggests impaired iron utilization. Think of them as red blood cells carrying 'iron baggage'.