Transferrin saturation

The transferrin saturation (TFS also TFS) is a derived parameter of iron metabolism , resulting from the concentration of iron and transferrin in the serum is calculated. Iron is not released in the plasma, but bound to the iron transport protein transferrin. The transferrin saturation value allows a statement to be made about the level of iron stores in the body of warm-blooded mammals. A decreased transferrin saturation (insufficient iron loading of the transferrin) indicates an iron deficiency , an increased transferrin saturation indicates iron overload ( hemochromatosis ) or increased iron release ( hemolysis ).

To answer the question of whether there is an iron deficiency, determining the transferrin saturation may be helpful. A disadvantage of the pure ferritin determination is that ferritin as an acute phase protein in infections, chronic inflammatory diseases and kidney insufficiency can be false-normal or even increased even with iron deficiency. Transferrin behaves the other way around in acute phase reactions, i.e. H. synthesis is diminished. When determining TFS, the value for C-reactive protein should therefore not be increased, otherwise an incorrect value will be measured. Since transferrin is synthesized in hepatocytes, the transferrin value increases when the liver is damaged and thus also influences the value of the TFS. The patient should be sober when the blood is drawn and this should be done in the morning. Another disadvantage of TFS is that the parameter is relatively insensitive. Iron deficiency states without significant anemia are not recorded.

The transferrin saturation TFS is calculated as follows from the values ​​for iron (Fe) [µg / dl] and transferrin (TF) [mg / dl]:

${\displaystyle TFS[\%]={\frac {Fe}{TF}}\cdot 70{,}9}$

The normal level of transferrin saturation is between 16 and 45%.

interpretation

Elevated

An increased transferrin saturation can z. B. occur in hemolytic anemia , aplastic anemia , anemia due to vitamin B12 , B6 or folic acid deficiency , hemochromatosis , multiple blood transfusions or liver diseases.

normal

A normal transferrin saturation can be found e.g. B. in iron distribution disorders ( tumor anemia , chronic inflammation, rheumatism , chronic kidney failure ).

Humiliated

The transferrin saturation can be reduced in the case of iron deficiency or iron deficiency anemia .

Web links

• Online calculation in different units

Literature and Sources

• Lothar Thomas: Laboratory and Diagnosis. 7.5 Transferrin saturation (TFS). 6th edition 2005. TH-Books Verlagsgesellschaft, ISBN 3-9805215-5-9 .
• Clara Camaschella: Iron Deficiency Anemia. In: NEJM . Volume 372, issue 19, 2015, doi : 10.1056 / NEJMra1401038 , pp. 1832–1843.

Individual evidence

1. ↑ ^{a b c} Transferrin saturation. In: DocCheck. Retrieved October 27, 2019 .