Transferrin
and Martina Feichter, medical editor and biologistMartina Feichter studied biology with an elective subject pharmacy in Innsbruck and also immersed herself in the world of medicinal plants. From there it was not far to other medical topics that still captivate her to this day. She trained as a journalist at the Axel Springer Academy in Hamburg and has been working for since 2007 - first as an editor and since 2012 as a freelance writer.
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Transferrin is the body's own transport protein for iron. Bivalent iron reaches the target cells via the bloodstream. Read here what role transferrin plays in iron metabolism, when it is determined and which diseases can influence transferrin levels.
What is transferrin?
Transferrin is an important part of our iron metabolism. It is responsible for the transport of iron in the bloodstream. If the protein is not yet covered by an iron molecule, it is called apotransferrin.
Iron transport in the bloodstream
Our body absorbs the trace element iron from food, for example from meat and offal, wheat bran and oat flakes. The iron then enters the blood via certain cells in the intestine, the enterocytes. There it is bound to the transport protein transferrin. Packaged in this way, it can be transported in the blood.
If a cell needs iron, it indicates this via an increased presentation of transferrin receptors - specific docking points for the transport protein on the cell surface. The loaded transferrin binds to these receptors and releases its iron to the cell.
Other forms of transferrin
There are two different forms of transferrin in the body that play a major diagnostic role: b2-transferrin and CDT (carbohydrate deficient transferrin).
The b2-transferrin occurs exclusively in the cerebral and synovial fluid. If the base of the skull breaks, cerebrospinal fluid can leak out of the nose or ear canal. So that the doctor can clarify whether it is not just a "runny nose", for example, he examines the secretion for b2 transferrin. If the test is positive, there is a fracture of the skull base.
The CDT, on the other hand, provides information about alcohol consumption over the past two to three weeks. It is determined, for example, in patients with addiction problems in order to identify changes in drinking behavior or a relapse.
When is transferrin determined?
The transferrin itself is of little importance for diagnosis. Nowadays, doctors clarify disorders in the iron metabolism by determining the iron level in the serum and the so-called transferrin saturation (TfS). It indicates how much iron is bound to a transport protein.
Transferrin saturation
If you want to learn more about this topic, read the post Transferrin Saturation.
Transferrin reference levels
Transferrin is made in the liver. If there is an increased need for iron, the liver increases production. Depending on the age, the blood serum normally contains the following amount of transferrin:
|
age
|
Transferrin normal value |
|
up to 7 days |
130-235 mg / dl |
|
8 days to 12 months |
156 - 321 mg / dl |
|
1 to 17 years |
174 - 446 mg / dl |
|
from 18 years |
200-360 mg / dl |
When is the transferrin decreased?
If the transferrin is low, there is usually iron overload. This can arise, for example, from increased blood transfusions or from the iron storage disease hemochromatosis.
The iron transport protein is also an anti-acute phase protein: This means that in the event of acute inflammation, the transferrin concentration decreases.
The transferrin level also drops if the liver function is impaired (e.g. due to severe cirrhosis).
When is the transferrin increased?
The most common reason for increased transferrin levels is iron deficiency. This can be the result of malnutrition or malnutrition, but it can also arise in the context of an iron absorption disorder - for example in chronic inflammatory bowel diseases (such as Crohn's disease) or in gluten-sensitive enteropathy (celiac disease). Another common cause of iron deficiency is chronic blood loss, such as that caused by menstrual bleeding in women.
An increase in the transferrin level can also be determined during pregnancy. Although there is no classic iron deficiency here, the body needs a particularly large amount of the trace element due to the development of the fetus.
What to do if the transferrin changes?
Treatment of altered transferrin levels depends on the underlying disease. Iron deficiency can often be treated by changing diet or taking iron tablets. In some cases, an iron supplement transfusion is also necessary.
If transferrin is low, the doctor should clarify the cause. If there is a suspicion of liver disease, he can, for example, determine the liver transaminases or other products of the liver cells in the blood and perform an ultrasound examination. If other inflammatory parameters in the blood are increased, such as the leukocyte count or the C-reactive protein, an acute infection is more likely to be the cause of the lowered transferrin value.
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