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Transferrin saturation blood test

In short

A typical adult transferrin saturation result is 20 to 50 %. A high saturation is often from a recent meal or iron supplements, since it follows serum iron. If it stays high on a repeat fasting test, doctors may check for inherited iron overload. Always read your result against the range printed on your own report.

How full the blood's iron carrier is, as a percent.

Transferrin is the protein that carries iron in blood, and this test shows how full it is. It is serum iron divided by TIBC, the most iron the carrier could hold, shown as a percent. Doctors use it to spot low iron and to screen for iron overload.

Is my Transferrin saturation high or low?

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Typical range

ForRangeUnit
Adults20–50%

Typical ranges for adults. Labs differ a little, so the range printed next to your result is the one to go by.

If your Transferrin saturation is high

A high saturation is often from a recent meal or iron supplements, since it follows serum iron. If it stays high on a repeat fasting test, doctors may check for inherited iron overload.

Common reasons

  • Iron supplements or an iron-rich meal before the test
  • Recent iron infusions or blood transfusions
  • An inflamed liver (hepatitis)
  • Red cells breaking down faster than usual (hemolysis)
  • Less often: hemochromatosis, an inherited condition that stores too much iron

If your Transferrin saturation is low

A low saturation is often a sign of too little iron for making red blood cells. It is also common with inflammation, so doctors read it with ferritin.

Common reasons

  • Low iron stores, most often from heavy periods or too little iron
  • A recent infection or ongoing inflammation
  • Pregnancy
  • Poor iron absorption, as with celiac disease or stomach surgery
  • Long-term kidney disease
  • Less often: slow, hidden bleeding from the stomach or bowel

What can throw it off

Because it is worked out from serum iron, meals, supplements and time of day can shift it.

Questions to take to your appointment

  1. 1Do my ferritin and saturation point the same way?
  2. 2Should this be repeated in the morning before I eat?
  3. 3Does my pattern fit low iron, too much iron or inflammation?

Read together with

Doctors rarely read Transferrin saturation alone. These usually sit next to it.

Quick answers

What is the transferrin saturation blood test?

Transferrin saturation: How full the blood's iron carrier is, as a percent. Transferrin is the protein that carries iron in blood, and this test shows how full it is. It is serum iron divided by TIBC, the most iron the carrier could hold, shown as a percent. Doctors use it to spot low iron and to screen for iron overload.

What is a normal transferrin saturation level?

For most adults, transferrin saturation is typically 20 to 50 %. Labs differ a little, so the range printed next to your result is the one to go by.

What does a high transferrin saturation mean?

A high saturation is often from a recent meal or iron supplements, since it follows serum iron. If it stays high on a repeat fasting test, doctors may check for inherited iron overload. Common reasons include iron supplements or an iron-rich meal before the test; recent iron infusions or blood transfusions; an inflamed liver (hepatitis); and red cells breaking down faster than usual (hemolysis). A doctor reads it together with your other results and how you feel.

What does a low transferrin saturation mean?

A low saturation is often a sign of too little iron for making red blood cells. It is also common with inflammation, so doctors read it with ferritin. Common reasons include low iron stores, most often from heavy periods or too little iron; a recent infection or ongoing inflammation; pregnancy; and poor iron absorption, as with celiac disease or stomach surgery.

What can affect my transferrin saturation result?

Because it is worked out from serum iron, meals, supplements and time of day can shift it.

What should I ask my doctor about my transferrin saturation?

Questions worth taking to the appointment: Do my ferritin and saturation point the same way? Should this be repeated in the morning before I eat? Does my pattern fit low iron, too much iron or inflammation?

What this page can’t do

It reads each number on its own.

Doctors read results together — ALT with AST, ferritin with hemoglobin, TSH with free T4. A pattern says more than any single flag.

It doesn't know you.

Your age, your medicines, how you feel and your last result all change what a number means.

It doesn't remember.

Close this page and your results are gone. That's on purpose: nothing was ever sent to us.

We also make Vita: Health Coach, an app for those parts. It reads your whole report with your medicines and history in mind, answers follow-up questions in plain words, and keeps your reports in one place — for you and for the people you look after.

Vita: Health Coach on the App Store

Sources

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