Transferrin
Transferrin is the plasma protein that carries iron from absorption sites and storage to the bone marrow. Direct measure of what TIBC estimates indirectly.
What it measures
Transferrin is the glycoprotein synthesized in the liver that binds and transports iron through circulation. Each molecule can carry up to two iron atoms; in steady-state physiology about 30% of transferrin is iron-saturated. Direct transferrin measurement gives the same clinical information as TIBC (which is calculated FROM transferrin) and is preferred in some labs because it is more reproducible.
What a high value can mean
- Iron-deficiency anaemia — body upregulates transferrin synthesis.
- Pregnancy, oral contraceptives — estrogen-driven rise.
What a low value can mean
- Anaemia of chronic disease — hepcidin downregulates.
- Iron overload / hemochromatosis — synthesis falls when stores are saturated.
- Protein-loss states — nephrotic syndrome, malnutrition, severe burns, advanced liver disease.
- Active inflammation, malignancy.
When to discuss with a doctor
Direct transferrin and TIBC tell the same story; if your lab reports one, the other is implied. Interpretation is always alongside serum iron and ferritin. Mediora.AI shows the full iron panel together.