High levels of total bilirubin and direct bilirubin in a blood test may suggest problems related to the liver, bile ducts, or increased breakdown of red blood cells.
What Is Bilirubin?
Bilirubin is a yellow pigment produced when old red blood cells are broken down. The liver processes this pigment and eliminates it from the body via bile (a digestive fluid) or urine. Blood tests typically measure both total bilirubin and direct bilirubin (also called “conjugated” bilirubin).
What Does a High Bilirubin Level Mean?
- Total Bilirubin includes both indirect (unconjugated) and direct (conjugated) forms of bilirubin in the blood.
- Direct Bilirubin refers to the form that has already been processed by the liver and is ready to be excreted.
What Causes Elevated Bilirubin?
A condition called hyperbilirubinemia (elevated bilirubin in the blood) can have various causes, depending on which type of bilirubin is elevated.
- Elevated Total Bilirubin
This may indicate problems occurring before, during, or after bilirubin is processed by the liver. Common causes include:
- Hemolysis – an accelerated breakdown of red blood cells
- Liver disease – such as hepatitis or cirrhosis
- Bile duct obstruction – for example, due to gallstones
- Elevated Direct Bilirubin
This usually means the liver is processing bilirubin but having trouble eliminating it. Common causes include:
- Bile duct obstruction – caused by gallstones, tumours, or scar tissue
- Liver conditions – such as hepatitis, cirrhosis, or liver injury
- Genetic disorders – that impair bilirubin transport from the liver
Common Symptoms of Elevated Bilirubin
- Jaundice – Yellowing of the skin and eyes.
- Dark-coloured urine
- Pale or clay-coloured stools
- Fatigue or abdominal pain (in some cases)
Laboratory Testing
- Liver function tests
Note: Fasting is not required before testing
References
- American Association for Clinical Chemistry. (2022). Bilirubin. [ labtestsonline.org ]
- MedlinePlus. (2023). Bilirubin blood test. U.S. National Library of Medicine. [ medlineplus.gov ]
- Schwartz, H. P., & Haberman, J. J. (2022). Hyperbilirubinemia. In StatPearls.StatPearls Publishing. [ ncbi.nlm.nih.gov ]
