Indirect Bilirubin
Bilirubin that has not yet been processed by the liver, calculated as total minus direct.
| Typical reference range | 0.2–1.2 mg/dL |
Ranges vary by laboratory, method, age and sex: always use the range printed on your own report. Why labs differ.
What it measures
Indirect (unconjugated) bilirubin is produced from the breakdown of hemoglobin and carried bound to albumin to the liver for processing. It is usually calculated rather than measured.
Why it matters
Elevated indirect bilirubin points to increased red cell breakdown or reduced liver conjugation, helping distinguish these from bile flow problems.
What a high result can mean
Causes include Gilbert's syndrome, hemolytic anemias, large bruises or hematomas being reabsorbed, ineffective red cell production (B12/folate deficiency) and some drugs (e.g. atazanavir).
What a low result can mean
Low values are not clinically significant.
What affects the result
Fasting and illness raise it in Gilbert's syndrome. Check hemoglobin, reticulocytes and LDH if hemolysis is suspected.
Units and conversion
Usually reported in mg/dL.
- From umol/L: multiply by 0.058 to get mg/dL
- From mmol/L: multiply by 58.48 to get mg/dL
Also called on lab reports
Bilirubin, Indirect, Bilirubin, Unconjugated, Bilirubin Indirect, Unconjugated Bilirubin, IBIL
Related tests: Liver
This page is educational and does not replace advice from a healthcare professional.