What it measures
Transferrin saturation shows what share of transferrin, the blood's iron carrier, is holding iron. It is not measured directly. The lab works it out as a percentage from serum iron and TIBC or transferrin.
Why people test it
- Used with ferritin to look for iron overload, such as haemochromatosis.
- Part of iron studies when tiredness or anaemia is being looked into.
- Checked in people with a family history of haemochromatosis.
Typical range
Ranges vary between labs with the method used, age and sex, and your report shows the lab's own range. One NHS trust's lab uses 16 to 40% for women and 16 to 50% for men. Source: University Hospitals of North Midlands NHS Trust pathology: Transferrin saturation (TSAT).
Finger-prick or vein?
A finger-prick sample is usually fine, as the figure is worked out from the same sample's iron and TIBC results.
Because it uses serum iron, it shifts through the day and after meals, and some labs ask for a fasting sample to confirm a raised result.
