Transferrin
The protein that transports iron in the blood. It tends to rise when iron stores are low.
Typical reference range
| Range | Unit |
|---|---|
| 2–3.6 | g/l |
What Transferrin measures
Transferrin is the protein that carries iron through your bloodstream, ferrying it from where it is absorbed or stored to the tissues that need it, such as the bone marrow that makes red blood cells.
Because it moves iron rather than storing it, transferrin is read as part of the iron studies panel, alongside serum iron, ferritin (a marker of iron stores), and transferrin saturation (how much of the transferrin is actually loaded with iron). Together these give a fuller picture than any single number.
Your liver adjusts how much transferrin it makes based on your iron status, producing more when iron is scarce and less when iron is plentiful. That responsiveness is what makes this marker informative when read in context.
What a high Transferrin can mean
A higher-than-expected transferrin value often reflects the body sensing that iron is in short supply.
- Iron deficiency is a common reason: when iron is scarce, the liver makes more carrier protein to grab whatever iron it can. This is typically seen alongside low ferritin and low transferrin saturation, since there is little iron to load onto all that extra transferrin.
- Pregnancy can raise transferrin as demand for iron increases.
- Estrogen, including from oral contraceptives, can also be associated with higher levels.
Because transferrin responds to several influences, a single high value is best understood as one piece of the iron panel rather than a finding on its own. If your iron studies are consistently high, it is worth discussing the overall pattern with a clinician, who can weigh it against your history before drawing conclusions.
What a low Transferrin can mean
A lower-than-expected transferrin value can arise for several different reasons, and it is not interpreted in isolation.
- Iron overload, where the body already holds plenty of iron and makes less carrier protein.
- Inflammation, since transferrin is a negative acute-phase protein and tends to fall when the body is fighting infection or injury.
- Liver disease, because the liver is where transferrin is made.
- Malnutrition or conditions that cause protein loss, which can lower many circulating proteins including transferrin.
Because these possibilities are so different, a low transferrin is read alongside ferritin and transferrin saturation to see which pattern fits. Interpretation depends on the whole picture together with your symptoms and history, so a clinician is best placed to make sense of the result and advise on any next steps.
Track your Transferrin over time in Quanome — it reads your lab reports (PDF or photo) on your device, charts each marker against its range, and an AI coach explains what your trends mean alongside your Apple Health and DNA.