Transferrin Saturation
The percentage of transferrin's iron-binding sites that are occupied by iron.
| Typical reference range (male) | 20–48 % |
| Typical reference range (female) | 16–45 % |
Ranges vary by laboratory, method, age and sex: always use the range printed on your own report. Why labs differ.
What it measures
Transferrin saturation is serum iron divided by TIBC, times 100. It describes how much iron is immediately available for red cell production and tissues.
Why it matters
Low saturation indicates insufficient iron supply to the marrow; persistently high saturation (above ~45%) is the key screening marker for hereditary hemochromatosis.
What a high result can mean
High values occur with hemochromatosis, recent iron supplementation, liver disease, hemolysis and transfusion-related iron overload.
What a low result can mean
Low values occur with iron deficiency and with anemia of inflammation or chronic disease.
What affects the result
Because serum iron fluctuates, test in the morning, fasting, without iron supplements for 24 hours. A high result is usually repeated before genetic testing for hemochromatosis (HFE).
Unit
Usually reported in %.
Also called on lab reports
Iron Saturation, % Saturation, Iron Saturation %, Iron % Saturation, TSAT, % Transferrin Saturation, Saturation, Transferrin, Iron Sat
Related tests: Iron Status
This page is educational and does not replace advice from a healthcare professional.