Perls's method is used to indicate "non-heme" iron in tissues such as ferritin and hemosiderin,[6] the procedure does not stain iron that is bound to porphyrin forming heme such as hemoglobin and myoglobin.[2] The stain is an important histochemical stain used to demonstrate the distribution and amount of iron deposits in liver tissue, often in the form of a biopsy.[6][7] Perls's procedure may be used to identify excess iron deposits such as hemosiderin deposits (hemosiderosis) and in conditions such as hereditary hemochromatosis.[8] Perls Prussian blue is commonly used on bone marrow aspirates to indicate levels of iron storage[4] and may provide reliable evidence of iron deficiency.[7]