Indirect bilirubin blood test
Indirect (unconjugated) bilirubin
In short
A typical adult indirect bilirubin result is under 0.8 mg/dL. A mild rise with other liver tests in range is most often due to Gilbert syndrome, a common, harmless trait. In Gilbert syndrome, the level rises further with fasting, illness or hard exercise. Always read your result against the range printed on your own report.
The part of bilirubin the liver has not yet processed.
Indirect bilirubin is the form made when old red blood cells break down, before the liver processes it. Labs usually work it out by subtracting direct bilirubin from total bilirubin. It rises when red cells break down faster or when the liver handles it slowly.
Is my Indirect bilirubin high or low?
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Typical range
| For | Range | Unit |
|---|---|---|
| Adults | under 0.8 | mg/dL |
| Adults | under 14 | µmol/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 Indirect bilirubin is high
A mild rise with other liver tests in range is most often due to Gilbert syndrome, a common, harmless trait. In Gilbert syndrome, the level rises further with fasting, illness or hard exercise.
Common reasons
- Gilbert syndrome, a harmless inherited trait (about 3 to 7 in 100 people)
- Fasting, dehydration, illness or hard exercise in the days before the test
- Some medicines, including some HIV medicines
- A large bruise or internal bleeding that the body is clearing
- Less often: red blood cells breaking down too fast (hemolysis)
What can throw it off
Fasting, illness and hard exercise can raise it for a few days, especially with Gilbert syndrome.
Questions to take to your appointment
- 1Could Gilbert syndrome explain this?
- 2Does my blood count suggest red cells are breaking down faster?
- 3Should I repeat the test after eating as usual?
Read together with
Doctors rarely read Indirect bilirubin alone. These usually sit next to it.
- Total bilirubinA yellow pigment made when old red blood cells break down.
- Direct bilirubinThe part of bilirubin the liver has already processed.
- HemoglobinThe protein in red blood cells that carries oxygen.
- Reticulocyte countYoung red blood cells, showing how fast new ones are made.
- LDHAn enzyme found in almost every cell of the body.
Quick answers
What is the indirect bilirubin blood test?
Indirect bilirubin (Indirect (unconjugated) bilirubin): The part of bilirubin the liver has not yet processed. Indirect bilirubin is the form made when old red blood cells break down, before the liver processes it. Labs usually work it out by subtracting direct bilirubin from total bilirubin. It rises when red cells break down faster or when the liver handles it slowly.
What is a normal indirect bilirubin level?
For most adults, indirect bilirubin is typically under 0.8 mg/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 indirect bilirubin mean?
A mild rise with other liver tests in range is most often due to Gilbert syndrome, a common, harmless trait. In Gilbert syndrome, the level rises further with fasting, illness or hard exercise. Common reasons include Gilbert syndrome, a harmless inherited trait (about 3 to 7 in 100 people); fasting, dehydration, illness or hard exercise in the days before the test; some medicines, including some HIV medicines; and a large bruise or internal bleeding that the body is clearing. A doctor reads it together with your other results and how you feel.
What can affect my indirect bilirubin result?
Fasting, illness and hard exercise can raise it for a few days, especially with Gilbert syndrome.
What should I ask my doctor about my indirect bilirubin?
Questions worth taking to the appointment: Could Gilbert syndrome explain this? Does my blood count suggest red cells are breaking down faster? Should I repeat the test after eating as usual?
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 StoreSources
- University of Rochester Medical Center — Indirect bilirubin
- ABIM — Laboratory Test Reference Ranges (January 2026)
- MedlinePlus Genetics — Gilbert syndrome
Stuck on a word? See the medical words. How we choose our sources. More about Vita Health Coach.