Bilirubin (Indirect)

LiverLiverCalculated

Bilirubin is a byproduct of broken-down old red blood cells. The bilirubin that travels to the liver for processing is unconjugated, meaning it is not water-soluble; it is bound to a protein in the blood called albumin, which helps carry it to the liver. Unconjugated bilirubin is normally worked out from the other bilirubin values rather than measured on its own, and it may appear as indirect bilirubin on test results.

Why it matters: A bilirubin test is one of a panel of liver function tests, and providers often use it to check on the health of the liver. High or low bilirubin levels might indicate that some part of the process of breaking down and clearing old red blood cells is not working correctly. Higher levels of unconjugated, or indirect, bilirubin might indicate haemolytic disease, sickle cell disease, or an adverse reaction to a blood transfusion.

Source · Cleveland Clinic — what it is, why it matters, what moves it, related conditions

Reference Range
< 19.0umol/L
19NormalHigh
What Moves It

May increase with:

The body breaking down red blood cells faster than the liver can keep up with
Conditions that affect the liver's ability to process bilirubin, which raise both types
Associated Conditions
Haemolytic diseaseSickle cell diseaseAdverse reaction to a blood transfusionIn newborns, premature birthIn newborns, a mismatched blood type between baby and motherIn newborns, reactions to substances in breast milk
Related Markers
Bilirubin (Total)Bilirubin (Direct)reticulocytes
Common questions

What is Bilirubin (Indirect)?

Bilirubin is a byproduct of broken-down old red blood cells. The bilirubin that travels to the liver for processing is unconjugated, meaning it is not water-soluble; it is bound to a protein in the blood called albumin, which helps carry it to the liver. Unconjugated bilirubin is normally worked out from the other bilirubin values rather than measured on its own, and it may appear as indirect bilirubin on test results.

What might a high or low Bilirubin (Indirect) mean?

A bilirubin test is one of a panel of liver function tests, and providers often use it to check on the health of the liver. High or low bilirubin levels might indicate that some part of the process of breaking down and clearing old red blood cells is not working correctly. Higher levels of unconjugated, or indirect, bilirubin might indicate haemolytic disease, sickle cell disease, or an adverse reaction to a blood transfusion.

What is the typical reference range for Bilirubin (Indirect)?

The general-population reference range shown here is < 19 umol/L. Reference ranges describe the general population and are not a personal target — discuss your results with your physician.

What can affect Bilirubin (Indirect)?

It may be higher with: The body breaking down red blood cells faster than the liver can keep up with, Conditions that affect the liver's ability to process bilirubin, which raise both types.

More in Liver
AlbuminAlkaline PhosphataseALTASTBilirubin (Direct)Bilirubin (Total)GGTLDH

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