Acute Phase Protein – Part 4 – Transferrin
Acute-phase protein (Acute Phase Reactants)
- Acute-phase protein is raised in inflammatory conditions.
- When there is an increase in a protein called positive acute-phase protein.
- In the case of a decrease in the acute phase protein, is called negative phase protein.
- The acute phase proteins (positive) are protein whose concentration increases in the plasma and after the disease episode is over then it decreases and may become normal.
- The patient blood is needed to prepare serum.
- Try to perform the analysis of the fresh sample.
- Can store at 4 °C for <72 hours.
- When stored at -20 °C, it is stable for 6 months.
- Avoid hemolysis because the RBC contains iron.
- Avoid lipemic serum.
- Differential diagnosis of anemia.
- Monitoring of treatment of iron deficiency anemia.
- This is a major beta-globulin (glycoprotein). This is an iron-carrying protein.
- This is also called as siderophilin.
- The transferrin transport the Ferric ion (Fe+++) and normally there is 20 to 30% saturation and it increases in the iron-deficiency anemia.
- One molecule of transferrin binds two ions of iron.
- Ferrous ions bind more rapidly than ferric ions.
- It changes in color from colorless to pink.
- The liver synthesizes the transferrin and this will binds the iron.
- This is synthesized in the liver and depends on its demands in anemia.
- This is decreased in acute inflammation and raised in a chronic condition.
- This acts as an acute-phase protein.
- Transferrin can be lost in the urine because of its small molecular size.
- More loss in severe proteinuria.
- CSF also contains a small amount of transferrin.
- Its function in the CSF is not known.
- This can be used as a marker in the case of CSF leakage.
- RBC has a receptor for the transferrin. These receptors also present in the lymphocytes.
- Transferrin level helps:
- In the case of iron deficiency anemia where transferrin level is increased.
- There is a low level of transferrin in the case of malignancy and inflammation.
- Functions of Transferrin:
- This transport iron.
- It regulates the absorption of iron.
- It protects against the toxic effects of iron.
- Its high level relates to the ability of the body to fight against the infection.
- Transferrin saturation is a better index of iron saturation.
- Transferrin saturation % = serum iron x 100 / TIBC
- o to 4 days = 130 to 275 mg/dL
- 3 months to 16 years = 203 to 360 mg/dL
- 16 to 60 years =
- male = 215 to 365 mg/dL
- female = 250 to 380 mg/dL
- 60 to 90 years = 190 to 375 mg/dL
- >90 years = 186 to 347 mg/dL
- Another source
- Male = 215 to 365 mg/dL
- Female = 250 to 380 mg/dL
- Newborn = 130 to 275 mg/dL
- Child = 203 to 360 mg/dL
- Source 4
- Adult = 250 to 425 mg/dL (2.5 to 4.2 g/L)
- Children = 203 to 360 mg/dL (2.0 to 3.6 g/L)
- Newborn = 130 to 275 mg/dL (1.3 to 2.7 g/L)
- Transferrin saturation:
- Male = 20% to 50%.
- Female = 15% to 50%
Transferrin level is increased in:
- Iron deficiency anemia.
- In pregnancy.
- Use of oral contraceptives or estrogen therapy.
Transferrin level is decreased in:
- In protein malnutrition.
- In protein loss from burns.
- In iron overload diseases (hemochromatosis).
- In acute and chronic diseases.
- Acute liver diseases.
- Renal diseases like nephrosis.
- The absence of the transferrin is seen in the genetic disorder called Atransferrinemia.
- It is characterized by anemia and hemosiderosis.
- Hemosiderosis is seen in the liver and heart.
Value for the layman:
- Transferrin is advised when the patient has anemia (decreased hemoglobin).
- This better test for the evaluation of anemia, iron deficiency, thalassemia, sideroblastic anemia, and hemochromatosis.