Serum iron is a

medical Medicine is the science and Praxis (process), practice of caring for patients, managing the Medical diagnosis, diagnosis, prognosis, Preventive medicine, prevention, therapy, treatment, Palliative care, palliation of their injury or disease, ...

laboratory test that measures the amount of circulating

iron Iron is a chemical element; it has symbol Fe () and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, forming much of Earth's o ...

that is bound to

transferrin Transferrins are glycoproteins found in vertebrates which bind and consequently mediate the transport of iron (Fe) through blood plasma. They are produced in the liver and contain binding sites for two Iron(III), Fe3+ ions. Human transferrin is ...

and freely circulate in the blood. Clinicians order this laboratory test when they are concerned about iron deficiency, which can cause anemia and other problems. 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, i.e. ferric iron, Fe³⁺; 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 ions that are bound to transferrin and circulating in the blood. This test should be done after 12 hours of fasting. The extent to which sites on transferrin molecules are filled by iron ions can be another helpful clinical indicator, known as percent transferrin saturation. Another lab test saturates the sample to measure the total amount of transferrin; this test is called

total iron-binding capacity Total iron-binding capacity (TIBC) or sometimes transferrin iron-binding capacity is a medical laboratory test that measures the blood's capacity to bind iron with transferrin. Transferrin can bind two atoms of ferric iron (Fe3+) with high affinit ...

(TIBC). These three tests are generally done at the same time, and taken together are an important part of the diagnostic process for conditions such as anemia, iron deficiency anemia, anemia of chronic disease and haemochromatosis.

Normal values

Normal reference ranges are: * Serum iron:Serum Iron
. University of Illinois Medical Center. Accessed July 6, 2006. ** Men: 65 to 176 μg/dL ** Women: 50 to 170 μg/dL ** Newborns: 100 to 250 μg/dL ** Children: 50 to 120 μg/dL * TIBC: 240–450 μg/dL * Transferrin saturation: 20–50% μg/dL = micrograms per deciliter. Laboratories often use different units and "normal" may vary by population and the lab techniques used; look at the individual laboratory

reference values A reference is a relationship between Object (philosophy), objects in which one object designates, or acts as a means by which to connect to or link to, another object. The first object in this relation is said to ''refer to'' the second object. ...

to interpret a specific test (for instance, your own). Blood values sorted by mass and molar concentration

Normal values

See also

References

Further reading