Transferrin is an iron transport protein in the blood that is one of the anti-acute phase proteins (see below). It transfers iron either to erythrocytes (red blood cells) as functional iron or to the reticuloendothelial system as storage iron. Transferrin saturation (TfS) can be calculated from transferrin and iron:
- TfS (%) = ( iron in μg/dl / transferrin in mg/dl ) x 70.9
- TfS (%) = ( iron in μmol/l / transferrin in mg/dl ) x 398
The procedure
Material needed
- Blood serum
Preparation of the patient
- Not necessary
Disruptive factors
- Not known
Normal value transferrin – adult
| Normal value in mg/dl | |
| Turbidimetric | 200-400 |
| Nephelometric | 212-360 |
Normal value transferrin – children
| Age | Normal value in mg/dl |
| <2 weeks | 158-268 |
| < 6 months | 202-302 |
| > 1 year | 261-353 |
| > 14 years | 240-360 |
Normal value transferrin saturation – adult
| Normal value in % | 16-45 |
Normal value transferrin saturation – children
| Age | Normal value in % |
| Preterm infants | 11,4-44,2 |
| Matured | 29,4-46,0 |
| <5 years | 7-44 |
| 6-9 years | 17-42 |
| 10-14 years | 11-36 (♀) 2-40 (♂) |
| 14-19 years | 6-33 |
Indications – Transferrin
- Suspected iron deficiency
- Suspicion of hemochromatosis
Indications – transferrin saturation (TSAT)
- Functional iron deficiency
- Suspected iron overload
Interpretation
Interpretation of elevated values – transferrin
- Iron deficiency (latent or manifest).
- Pregnancy
Interpretation of decreased values – transferrin
- Acute inflammation, unspecified (anti-acute phase protein = negative APP).
- Protein loss syndromes
- Enterally such as exudative enteropathy.
- Renal such as nephrotic syndrome
- Chronic inflammation, unspecified (infectious anemia).
- Hemochromatosis (iron storage disease).
- Hemoglobinopathy (diseases caused by disorders in the formation of hemoglobin (red blood pigment)), such as thalassemia.
- Liver cirrhosis – connective tissue remodeling of the liver, which leads to functional impairment.
- Neoplasms, unspecified (tumor anemia).
Interpretation of elevated values – transferrin saturation (= V. a. iron overload).
- Primary (genetic) hemochromatosis (iron storage disease).
- Secondary hemochromatosis due to:
- Blood transfusions, clustered.
- Chronic inflammation, unspecified; infectious anemia.
- Hemolysis (dissolution of red blood cells);
- Hemoglobinopathy (diseases caused by disorders in the formation of hemoglobin (red blood pigment)), e.g., thalassemia.
- Neoplasms, unspecified (tumor anemia).
- Lead poisoning
- Hypersiderinemic anemia (including drug-induced anemia).
- Megaloblastic anemia – form of anemia caused by a deficiency of vitamin B12 or folic acid.
Interpretation of decreased values – transferrin saturation.
- Iron deficiency
- Chronic infections, unspecified
- Liver parenchymal damage
- Neoplasia (neoplasms)
- Uremia (occurrence of urinary substances in the blood above normal values).
Other indications
- Transferrin reacts as an anti-acute phase protein (= negative APP). This means that a decreased transferrin value may be decreased due to inflammation and would otherwise be in the normal range. Therefore, transferrin should be assessed in parallel with C reactive protein (acute-phase protein).
- Ferritin and transferrin concentration always behave oppositely, i.e. transferrin reacts only when the iron stores are already depleted.