Total iron binding capacity (TIBC)

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The TIBC value (total serum iron-binding capacity) reflects the concentration of transferrin, a carrier protein of iron ions in the serum. Under normal conditions, about 1/3 of the transferrin is saturated with iron. The difference between the TIBC value and the Fe concentration shows how much of the transferrin is unbound with iron.

What is TIBC?

TIBC is a laboratory test that can help estimate the amount of iron needed to fully saturate transferrin (a protein produced by the liver). Transferrin is present in serum and is responsible for iron binding, regulates its absorption into the blood and transport in the serum. Iron, in turn, is a very important element for the body, necessary for its functioning. It is usually absorbed in the duodenum or upper small intestine.

The difference between the TIBC value and the Fe concentration reflects the unbound amount of transferrin. We can identify two sources of iron:

  1. heme, contained in animal products, which is easily absorbed by the body,
  2. non-heme, which is found, inter alia, in plant products, unfortunately, it is more difficult for the human body to absorb.

In the TIBC study, the iron transferrin saturation is calculated using the appropriate formula, where Tf corresponds to the measured concentration of transferrin. Whereas “iron” is the level of determined iron in the blood: TfS (%) = Iron / Tf x 100.

The results of TIBC on transferrin saturation and its total iron binding capacity are related because transferrin is the only protein with the ability to transport iron. There is a formula for this: TfS (%) = Iron / THD x 100

When do we test the total iron binding capacity of the serum?

The indications for the TIBIC study are listed below.

1. Simultaneously with the determination of iron concentration in the differentiation of the cause of anemia.

2. Suspicion of excessive iron deposition in the body.

3. Suspicion of insufficient iron saturation.

4. Microcytic anemia.

5. Assessment of the proper functioning of the liver.

6. Presence in the family of cases of familial hemochromatosis.

7. Suspicion of inflammatory and neoplastic diseases.

TIBC examination – how are the tests performed?

  1. Material for TIBC testing: serum.
  2. Preparation for the examination: the patient should be fasting (at least 8 hours). The last meal is recommended to be eaten at 18 p.m. on the day preceding the examination.
  3. The course of the TIBC examination: one-time blood sampling from the ulnar vein (preferably visible). In children, a small lancet incision is made in the skin to cause a little bleeding. Then the collected sample is sent for further analysis.
  4. Waiting time for the TIBC result: 1 day.
  5. Norma: 44,8-73,4 µmol/l (250-410 µg/dl).

Comments: In the case of overt or latent iron deficiency, the TIBC value is increased. In the case of inflammatory and neoplastic diseases, TIBC is lowered. Persons performing the test of the total capacity of serum to bind iron should inform about all taken drugs, as some of them may affect the result of the test, e.g. contraceptive pills or preparations containing fluoride in their composition.

How should the results of the TIBC study be analyzed?

Standards for TIBC Test (Gender dependent):

  1. Concentration: 45-70 μmol/l (251-391 μg/dl),
  2. Women: 40-80 µmol / L (223-446 µg / dL).

What does elevated TIBC mean?

  1. taking oral contraceptives,
  2. estrogen treatment therapies,
  3. an actual iron deficiency, e.g. in pregnant women.

What does a reduced TIBC level mean?

  1. hemosiderosis,
  2. nephrotic syndrome (damage to the kidneys with a significant loss of protein in the urine),
  3. polycythemia,
  4. acute or chronic infections
  5. cirrhosis of the liver and its other ailments,
  6. frequent blood transfusions
  7. tumors,
  8. haemochromatosis (if you suspect iron overabsorption, perform Hemochromatosis – a genetic test for the most common mutations – the test is available by mail order on Medonet Market,
  9. malnutrition of the body,
  10. anemia in the course of chronic diseases,

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