Direct bilirubin blood test
Direct (conjugated) bilirubin
In short
A typical adult direct bilirubin result is under 0.3 mg/dL. A small rise can come with a passing illness or a medicine. Because it points to the liver or bile ducts, doctors usually look into it more than a high indirect bilirubin. Always read your result against the range printed on your own report.
The part of bilirubin the liver has already processed.
Direct bilirubin is the part the liver has already processed, ready to leave in bile, a digestive juice. It rises when the liver struggles to pass it on, or when the tubes that drain bile are blocked. So a high result points toward the liver or bile ducts rather than the blood.
Is my Direct bilirubin high or low?
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Typical range
| For | Range | Unit |
|---|---|---|
| Adults | under 0.3 | mg/dL |
| Adults | under 5 | 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 Direct bilirubin is high
A small rise can come with a passing illness or a medicine. Because it points to the liver or bile ducts, doctors usually look into it more than a high indirect bilirubin.
Common reasons
- Some medicines, including some antibiotics, that slow bile flow
- Gallstones that block the bile duct
- A viral infection that inflames the liver, such as mono (mononucleosis)
- Liver inflammation from heavy drinking
- Less often: a rare harmless inherited trait (Dubin-Johnson or Rotor syndrome)
- Less often: liver scarring (cirrhosis) or a narrowed bile duct
- Less often: a tumor in the pancreas or bile ducts
Questions to take to your appointment
- 1Are my ALP and GGT high too?
- 2Could any of my medicines slow bile flow?
- 3Would an ultrasound of my liver and bile ducts help?
Read together with
Doctors rarely read Direct bilirubin alone. These usually sit next to it.
Quick answers
What is the direct bilirubin blood test?
Direct bilirubin (Direct (conjugated) bilirubin): The part of bilirubin the liver has already processed. Direct bilirubin is the part the liver has already processed, ready to leave in bile, a digestive juice. It rises when the liver struggles to pass it on, or when the tubes that drain bile are blocked. So a high result points toward the liver or bile ducts rather than the blood.
What is a normal direct bilirubin level?
For most adults, direct bilirubin is typically under 0.3 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 direct bilirubin mean?
A small rise can come with a passing illness or a medicine. Because it points to the liver or bile ducts, doctors usually look into it more than a high indirect bilirubin. Common reasons include some medicines, including some antibiotics, that slow bile flow; gallstones that block the bile duct; a viral infection that inflames the liver, such as mono (mononucleosis); and liver inflammation from heavy drinking. A doctor reads it together with your other results and how you feel.
What should I ask my doctor about my direct bilirubin?
Questions worth taking to the appointment: Are my ALP and GGT high too? Could any of my medicines slow bile flow? Would an ultrasound of my liver and bile ducts help?
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.
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