Iron, Serum Blood Test
Iron, Serum Blood Test - this test measures the amount of iron which is bound to transferrin. See TIBC.
"65% of the iron in the body is bound up in hemoglobin molecules in red blood cells. About 4% is bound up in myoglobin molecules. Around 30% of the iron in the body is stored as ferritin or hemosiderin in the spleen, the bone marrow and the liver. Small amounts of iron can be found in other molecules in cells throughout the body. None of this iron is directly accessible by testing the serum.
"However, some iron is circulating in the serum. Transferrin is a molecule produced by the liver that binds one or two iron(III) ions; transferrin is essential if stored iron is to be moved and used.
"Most of the time, about 30% of the available sites on the transferrin molecule are filled. The test for serum iron uses blood drawn from veins to measure the iron molecules that are bound to transferrin, and circulating in the blood."