What it measures
Transferrin is the protein, made in the liver, that carries iron in the blood. The test measures how much is present. It is often used to work out how much of the blood's iron-carrying capacity is in use, called transferrin saturation.
Why people test it
- Part of iron studies, read with ferritin and serum iron when looking into low or high iron.
- Used to work out transferrin saturation, a measure of how much iron is available.
- Measured when tiredness or anaemia prompts a look at iron levels.
- Part of the iron studies some endurance athletes check alongside ferritin.
Typical range
Ranges vary by lab, method, age and sex, and your report shows the lab's own range. One NHS trust gives 2.3 to 4.0 g/L. Source: Worcestershire Acute Hospitals NHS Trust: Iron Studies.
Finger-prick or vein?
Both routes are offered, though most providers take it from a vein.
