Transferrin, TIBC, UIBC (clinical analyzes)



Transferrin is a glycoprotein produced by the liver and is the most important protein for the binding and transport of iron in the body. The iron taken from food is absorbed in the intestine, binds to transferrin and, as needed, is transported by the blood to various organs and mainly to the bone marrow, where about 70% of the iron taken from food is incorporated into the " part of the "heme" group of hemoglobin, a protein found in red blood cells, which has the function of distributing oxygen from the lungs to the whole organism. The remaining 30% is stored in the tissues in the form of ferritin or hemosiderin.

Through tests for the dosage of transferrin (transferrinemia), TIBC, UIBC and transferrin saturation it is possible to evaluate the ability of the blood circulation to transport and bind iron:

  • transferrinemia: measures the direct dosage of transferrin in the blood
  • TIBC (Total Iron Binding Capacity): evaluates the total ability of blood proteins to bind iron. Since transferrin is the major protein for iron-binding capacity, this test provides a good approximation of the amount of transferrin available.
  • UIBC (Unsatured Iron Binding Capacity): measures the level of transferrin still not saturated by iron (the reserve transferrin)
  • transferrin saturation: it is a calculation that, using the iron, TIBC and UIBC values, allows to evaluate the percentage of transferrin saturated by iron (how much it has bound)

The test of the transferrin dosage (transferrinemia) can be prescribed by the doctor in the case in which the presence of abnormal iron metabolism is suspected, to evaluate the nutritional status and liver function. The levels of this protein decrease in case of liver disease and, also, in relation to a diet characterized by a low protein intake.

Generally the TIBC or UIBC tests are requested by the doctor together with the blood iron test if there is a suspicion of a state of iron deficiency or excess.

The TIBC test may be ordered with the ferritin test if iron accumulation is suspected or if you are familiar with a genetic disorder (hemochromatosis), where the body's ability to absorb iron is impaired causing the accumulation of iron. element in the tissues which, slowly, are damaged.

The test

The tests are carried out by simply drawing blood from the vein of an arm. Fasting for at least twelve hours is required before undergoing tests. After the blood collection, you can immediately return to normal activities.

As a rule, drugs do not affect the outcome of the examination except in the case in which you are following an iron-based therapy or following the use of oral contraceptives, so it is important that the doctor is aware of them.

It is also good to know that the state of pregnancy affects the results of the tests.


Elevated levels of TIBC, UIBC or transferrin may be due to iron deficiency.

Low levels of TIBC, UIBC or transferrin in the blood can be associated with:

  • liver disease
  • hemochromatosis, a genetic pathology
  • acute infections or persistent over time (chronic)
  • inflammatory states
  • malnutrition
  • some types of anemia
  • nephrotic syndrome, kidney disease characterized by the loss of protein in the urine

The saturation of transferrin increases in the presence of high amounts of iron in the blood (for example in the case of iron poisoning), it decreases as a result of its deficiency.

The reading and interpretation of the test results must always be performed by the attending physician who knows the history of the health of his patients.

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