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ANEMIAS AND OTHER RED CELL DISORDERS - PART 4

Mức độ sắt huyết thanh bình thường dao động giữa 50 và 150 mg / dL, tất cả các ràng buộc để transferrin. TIBC phản ánh số lượng tối đa của sắt huyết thanh transferrin có thể gắn. Phạm vi giá trị bình thường giữa 250 và 375 mg / dL. Phạm vi rộng của giá trị bình thường đối với sắt huyết thanh | CHAPTER 7 IRON DEFICIENCY 105 The serum iron level normally ranges between 50 and 150 mg dL all of it bound to transferrin. The TIBC reflects the maximum quantity of iron that serum transferrin can bind. The normal value ranges between 250 and 375 mg dL. The broad range of normal values for both the serum iron and the TIBC diminishes the utility of isolated values for either parameter. These tests instead are best used to determine the transferrin saturation which is the ratio of the serum iron to the TIBC. The transferrin saturation usually ranges between 20 and 50 . Adult males have higher normal values than do females. Severe iron deficiency often drives the transferrin saturation to below 10 . Some laboratories measure the quantity of transferrin protein in the serum and report results in milligrams of protein per deciliter of serum. Health-care providers sometimes assume incorrectly that the serum transferrin value is the same as the TIBC. The two are related but not synonymous. Transferrin is the sole plasma protein that binds iron. The TIBC therefore depends on the quantity of transferrin in the plasma. A mathematical conversion is needed to directly connect the two however. The serum ferritin value expressed in nanograms of protein per milliliter is proportional to body iron stores. Normal values range between 10 and 200 ng mL for reproductive-age women and between 15 and 400 ng mL for men.28 Ethnic and racial variations in serum ferritin levels likely represent population trends in body iron stores.29 Serum ferritin levels in postmenopausal women approximate those of their male counterparts. The serum ferritin value alone often can be used to estimate the iron status of a patient. A common point of confusion regarding the relationship of serum ferritin and serum iron arises from the fact that ferritin is the storehouse for intracellular iron.30 Ferritin molecules within cells are multi-subunit spherical shells that can sequester more than 4000 iron atoms.