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TIBC blood test

Total iron-binding capacity

In short

A typical adult TIBC result is 250 to 450 µg/dL. A high TIBC is a common sign of low iron stores. Late pregnancy and birth control pills can also raise it. Always read your result against the range printed on your own report.

How much iron the blood's iron carrier could hold.

TIBC shows how much iron the blood could carry if transferrin, its iron-carrying protein, were full. When iron stores run low, the body makes more transferrin, so TIBC goes up. The lab divides serum iron by TIBC to get transferrin saturation, how full the carrier is.

Is my TIBC high or low?

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Typical range

ForRangeUnit
Adults250–450µg/dL
Adults45–81µmol/L

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

If your TIBC is high

A high TIBC is a common sign of low iron stores. Late pregnancy and birth control pills can also raise it.

Common reasons

  • Low iron stores, most often from heavy periods or too little iron
  • Late pregnancy
  • Birth control pills or hormone therapy
  • Less often: slow, hidden bleeding from the stomach or bowel

If your TIBC is low

A low TIBC often goes with inflammation, liver disease or poor nutrition, when the body makes less carrier protein. It can also go with too much stored iron.

Common reasons

  • A recent infection or ongoing inflammation
  • Low protein levels, from poor nutrition or illness
  • Iron overload, such as hemochromatosis (an inherited iron-storage condition)
  • Less often: liver scarring (cirrhosis) or kidney disease that leaks protein

What can throw it off

Birth control pills, hormone therapy and pregnancy can raise TIBC, while inflammation lowers it.

Questions to take to your appointment

  1. 1What do my iron and TIBC together say about my iron stores?
  2. 2Should my ferritin be checked too?
  3. 3Could my medicines or a recent illness affect this?

Read together with

Doctors rarely read TIBC alone. These usually sit next to it.

Quick answers

What is the TIBC blood test?

TIBC (Total iron-binding capacity): How much iron the blood's iron carrier could hold. TIBC shows how much iron the blood could carry if transferrin, its iron-carrying protein, were full. When iron stores run low, the body makes more transferrin, so TIBC goes up. The lab divides serum iron by TIBC to get transferrin saturation, how full the carrier is.

What is a normal TIBC level?

For most adults, TIBC is typically 250 to 450 µg/dL. Some countries print it in µmol/L, so check the unit first. Labs differ a little, so the range printed next to your result is the one to go by.

What does a high TIBC mean?

A high TIBC is a common sign of low iron stores. Late pregnancy and birth control pills can also raise it. Common reasons include low iron stores, most often from heavy periods or too little iron; late pregnancy; birth control pills or hormone therapy; and less often: slow, hidden bleeding from the stomach or bowel. A doctor reads it together with your other results and how you feel.

What does a low TIBC mean?

A low TIBC often goes with inflammation, liver disease or poor nutrition, when the body makes less carrier protein. It can also go with too much stored iron. Common reasons include a recent infection or ongoing inflammation; low protein levels, from poor nutrition or illness; iron overload, such as hemochromatosis (an inherited iron-storage condition); and less often: liver scarring (cirrhosis) or kidney disease that leaks protein.

What can affect my TIBC result?

Birth control pills, hormone therapy and pregnancy can raise TIBC, while inflammation lowers it.

What should I ask my doctor about my TIBC?

Questions worth taking to the appointment: What do my iron and TIBC together say about my iron stores? Should my ferritin be checked too? Could my medicines or a recent illness affect this?

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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