Bilirubin is a blood test that measures bilirubin levels in the blood. Normal range: Total bilirubin is typically below 20 μmol/L. Visible yellowing of the skin and eyes (jaundice) usually appears above about 40-50 μmol/L. When raised, labs split it into conjugated (direct) and unconjugated (indirect) fractions to find the cause.. It is commonly used to helps assess liver function and can identify issues with bile flow or red blood cell breakdown..
What is Bilirubin?
A yellow pigment produced during the breakdown of red blood cells.
Why is it measured?
Helps assess liver function and can identify issues with bile flow or red blood cell breakdown.
Normal Reference Range
Total bilirubin is typically below 20 μmol/L. Visible yellowing of the skin and eyes (jaundice) usually appears above about 40-50 μmol/L. When raised, labs split it into conjugated (direct) and unconjugated (indirect) fractions to find the cause.
Note: Reference ranges may vary between laboratories. Always consult your healthcare provider for interpretation.
What Causes High BILIRUBIN?
High bilirubin causes jaundice and points to one of three problems: too much red cell breakdown (haemolysis, raising unconjugated bilirubin), liver cell damage (hepatitis, cirrhosis), or blocked bile flow (gallstones or a tumour, raising conjugated bilirubin). A very common and entirely benign cause is Gilbert's syndrome, an inherited variant in which unconjugated bilirubin rises during fasting, illness or stress without any liver disease. Newborn jaundice is a separate, expected phenomenon.
What Causes Low BILIRUBIN?
Low bilirubin has no clinical significance and requires no action.
How Often Should BILIRUBIN Be Tested?
Bilirubin is part of routine liver function tests. When elevated, it is fractionated (conjugated vs unconjugated) and followed by liver enzymes, a blood film and imaging as needed to pinpoint the cause. It is monitored in known liver or biliary disease.
Related Blood Markers
Bilirubin is interpreted with ALT and AST (liver cell injury), ALP and GGT (bile flow), and, when haemolysis is suspected, the full blood count, reticulocytes, LDH and haptoglobin.
Key Facts
- •Category: Vital Organ Functions
- •Unit of Measurement: μmol/L
- •Test Code: BILIRUBIN
Related Vital Organ Functions Markers
Albumin
The main protein in blood plasma, produced by the liver.
Learn moreALP (Alkaline Phosphatase)
An enzyme found primarily in the liver and bones.
Learn moreALT (Alanine Transaminase)
ALT (Alanine Transaminase, also written ALAT or SGPT) is an enzyme concentrated in the liver. When liver cells are damaged, ALT leaks into the bloodstream, so it is the single most liver-specific enzyme on a standard Liver Function Test (LFT). It is often interpreted alongside AST, GGT and ALP to build a picture of liver health.
Learn moreAST (Aspartate Transaminase)
AST (Aspartate Transaminase, also written ASAT or SGOT) is an enzyme found in the liver, heart, skeletal muscle and red blood cells. Because AST exists in multiple tissues, it is less liver-specific than ALT. Pathology labs report AST as part of the standard Liver Function Test (LFT) panel.
Learn moreBUN (Blood Urea Nitrogen)
A waste product filtered by the kidneys.
Learn moreCreatinine
A waste product produced by muscles and filtered by the kidneys.
Learn more