Home › Biomarkers › Transferrin saturation
Transferrin saturation is an important measure of the iron in your body. A low value can point to iron deficiency, a high value can point to too much iron.[1]
On this page you can read what transferrin saturation is, what the guidelines say about a value that is too low or too high, what affects your value and which values are best looked at alongside it.
Also known as: TSAT, iron saturation. At the lab: n/a.
Transferrin is a protein in your blood. It carries iron between the tissues of your body, in a form that dissolves and is not toxic. It also captures free iron that could otherwise cause damage.[1]
Transferrin saturation is a measure that takes into account the iron in your blood and transferrin together. In this way, the value gives a picture of the iron stores in your body.[1]
Labs can measure the value in different ways. Because these methods are increasingly available, the value is used in many healthcare systems.[1]
Your body needs iron for many processes. It keeps the amount of iron in balance with the help of several proteins. Too little and too much iron can both be harmful.[1]
In practice, doctors often use transferrin saturation to detect iron deficiency or too much iron. The test does have its limits, especially when there is inflammation. That is why careful reading is needed to avoid the wrong conclusions.[1]
Research also links the value to death from a condition of the heart and blood vessels. That evidence comes mainly from observational research. More well-designed research is needed to see what the value really tells us here.[1]
Your result shows the lab's reference range next to your value. The lab calls a value within the limits of that range normal.
| Value | What it can mean | Who it is for |
|---|---|---|
| Low[1] | Can point to iron deficiency | Adults whose iron status is being checked by a doctor |
| High[1] | Can point to too much iron in the body | Adults whose iron status is being checked by a doctor |
| Low or high when there is inflammation[1] | Harder to read, can lead to the wrong conclusion | People with inflammation |
Source: a review article by Elsayed and colleagues on transferrin saturation as a measure of iron in the body. The article does not give fixed cut-off values.[1]
A low transferrin saturation can point to iron deficiency. When there is inflammation, the value can be misleading, so a doctor assesses your result in context.[1]
A high transferrin saturation can point to too much iron in your body. Here too, a doctor looks at the whole picture before anything can be said about it.[1]
BioProfile is working on its own zones for each value, from risk to optimal. A doctor reviews those zones before they appear in your result.
The value takes into account both the iron in your blood and transferrin. So both count towards the result.[1]
When there is inflammation, the value is less reliable to read. That can lead to the wrong conclusion if you do not take it into account.[1]
Labs estimate the value using different methods, such as turbidimetry, nephelometry and immunochemistry. Each test has its own limits.[1]
Transferrin saturation is included in all five packages, from BioProfile 31 to BioProfile 150.[2]
The BioProfile editorial team wrote this page on 5 October 2026 from the sources below, which we read on 5 October 2026. Every number on this page appears in one of those sources, with that source's number next to it. An expert has yet to review this page; once that review is done, the expert's name and the date of the review will appear at the top. This page explains and does not diagnose. Discuss a value outside the normal range with your GP.
