Serum Iron Levels
Serum iron levels are a direct measure of total iron circulating in the blood [either bound to transferrin (90%) or ferritin (10%)]. It helps to evaluate the state of the body’s iron stores. A higher-than-normal value indicates that you have got a surplus of iron circulating in your blood (This can be an indication of Haemochromatosis), while a lower value may indicate an iron deficiency such as Anaemia.
Ferritin
Ferritin is an intracellular protein that holds and stores iron in the body. Typically, ferritin is found inside the cells, but a small amount is also released in the blood and helps transfer iron from one body site to another. Hence, plasma ferritin levels are also a good indicator of iron stores of the body.
The ferritin test is the most sensitive test to evaluate the iron levels in the body.
Ferritin levels are tested as a part of Iron Status Profile. Ferritin levels show a direct correlation to the total iron stores in the body.
However, Ferritin may also be high in the blood due to other conditions like chronic inflammation.
Transferrin Saturation
Transferrin is a protein that tightly but reversibly holds the iron molecules and transfers it to different parts of the body where it is needed.
Transferrin protein has multiple sites on which iron binds and gets transferred. The iron saturation on these transferrin sites is a good indicator of total iron levels in the body.
Usually, only 30% of these sites in transferrin protein are saturated by the iron molecules.
A Transferrin Saturation value below 20% indicates an iron deficiency in the body, which is the leading cause of anaemia. As there is less iron in the body, there is less iron available to saturate the sites on transferrin.
A Transferrin Saturation value above 50% indicates iron excess (hemochromatosis) in the body.
Total Iron-Binding Capacity (TIBC)
Total iron-binding capacity (TIBC) is the measure of your bloods ability to hold and carry iron molecules i.e. it is the ability of the transferrin in blood to bind iron.
The same is with transferrin and ferritin in the blood. The more iron bound to these proteins, the less is their remaining capacity to stock more iron.
TIBC is measured as a part of Iron Status Profile and gives an inverse measure of the body’s iron stores. Higher the TIBC, the lesser the amount of iron in the body.
