Bone marrow iron staining applies the principle of Prussian blue reaction between trivalent iron ions and acidic potassium ferricyanide solution to examine the amount of iron in the bone marrow to determine the disease. There is also extracellular iron, known as ferricyanin, and intracellular iron in the bone marrow. If the bone marrow iron staining value is low, the extracellular iron content is generally low and predisposes to iron deficiency anemia. If the bone marrow iron staining value is high, the extracellular iron content is increased, and the most common pathologies are aplastic anemia, uremia, leukemia, and myelodysplastic syndrome.