Bilirubin (Total)
Bilirubin is a yellow-orange pigment produced when the liver breaks down old red blood cells. The liver processes bilirubin and excretes it through bile into the intestines. When the liver is damaged or bile flow is blocked, bilirubin accumulates in the blood, causing jaundice (yellowing of skin and eyes). Total bilirubin includes both direct (conjugated) and indirect (unconjugated) forms.
Reference Ranges
Male
0.1 – 1.2
mg/dL
Female
0.1 – 1.2
mg/dL
Child
0.1 – 1
mg/dL
Ages 1–18
Reference ranges may vary by laboratory. Always compare with the range printed on your lab report.
What Low Levels Mean
Low bilirubin has no clinical significance and is normal. Some research suggests very low bilirubin may indicate lower antioxidant protection, as bilirubin has mild antioxidant properties, but this is not clinically actionable.
What High Levels Mean
High bilirubin causes jaundice when it exceeds ~2.5 mg/dL. Causes include liver disease (hepatitis, cirrhosis), bile duct obstruction (gallstones, tumors), hemolytic anemia (excess red cell destruction), and Gilbert syndrome (a common, harmless genetic variant affecting 5–10% of people).
Frequently Asked Questions
What is Gilbert syndrome?
Gilbert syndrome is a common, harmless genetic condition where the liver is slightly slower at processing bilirubin. It affects 5–10% of people and causes mild, intermittent jaundice — especially during fasting, stress, or illness. No treatment is needed.
What does it mean if direct bilirubin is high?
Direct (conjugated) bilirubin elevation suggests a blockage in bile flow — gallstones, bile duct obstruction, or liver disease affecting bile secretion. Indirect (unconjugated) elevation suggests excess red cell breakdown or processing issues like Gilbert syndrome.
Can high bilirubin damage the body?
In adults, mildly elevated bilirubin is usually harmless. Very high levels (>20 mg/dL) can indicate severe liver failure. In newborns, high bilirubin is more dangerous — it can cross the blood-brain barrier and cause brain damage (kernicterus), which is why neonatal jaundice is closely monitored.
This information is for educational purposes only and should not replace professional medical advice. Always consult your doctor for interpretation of your test results.
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