Bilirubin is a yellowish pigment that is created during the normal, daily breakdown of old red blood cells. The liver's job is to process this bilirubin so it can be excreted from the body in stool.
When the liver is healthy, it clears bilirubin efficiently. If the liver is damaged, or if the bile ducts are blocked, bilirubin builds up in the blood. When levels get high enough, this yellow pigment deposits in the skin and the whites of the eyes, causing a condition known as jaundice.
Typical Total Bilirubin reference ranges (mg/dL)
| Adults | 0.1 – 1.2 | Ranges vary slightly by lab |
|---|
Total bilirubin includes both 'direct' (processed by the liver) and 'indirect' (unprocessed) bilirubin.
What high bilirubin means
A high bilirubin level means either that too many red blood cells are breaking down too quickly, or that the liver is failing to clear the bilirubin from the blood. Common causes include viral hepatitis, cirrhosis, or a blockage in the bile ducts (like a gallstone).
There is also a very common, harmless genetic condition called Gilbert's syndrome, which affects about 5-10% of the population. People with Gilbert's syndrome have a mild, chronic elevation in bilirubin (usually between 1.2 and 3.0 mg/dL) but completely normal liver enzymes. It requires no treatment and is not dangerous.
Direct vs. Indirect Bilirubin
If your total bilirubin is high, your doctor may look at the breakdown between 'direct' (conjugated) and 'indirect' (unconjugated) bilirubin. If indirect is high, it points toward red blood cell breakdown or Gilbert's syndrome. If direct is high, it points toward a liver problem or a blocked bile duct.
When to actually worry — and when not to
- If you notice your skin or the whites of your eyes turning yellow, or if your urine becomes very dark (like tea), contact a doctor promptly, as this indicates a significant bilirubin buildup.
- A mildly elevated bilirubin with completely normal AST, ALT, and Alkaline Phosphatase is very often just Gilbert's syndrome, but your doctor should confirm this.
Common questions
What does a low bilirubin mean?
Low bilirubin is generally not a cause for concern and is considered normal.
Why do newborns get high bilirubin?
Newborn jaundice is very common because a baby's liver isn't fully mature yet and can't process bilirubin quickly enough. It usually resolves on its own or with light therapy (phototherapy).
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Upload your reportMedical disclaimer: This article is for educational and informational purposes only and does not constitute medical advice, diagnosis, or treatment. Reference ranges vary between laboratories — always compare your result to the range on your own report, and consult a qualified healthcare professional about your results and any symptoms.