What it is: A bilirubin test measures the level of bilirubin — a yellow pigment produced when red blood cells break down — in the blood, usually as total, direct (conjugated), and indirect (unconjugated) values.
Why it's ordered: Ordered as part of a liver panel when a provider suspects liver disease, bile duct blockage, or a condition causing excess red blood cell breakdown (hemolysis), or when someone shows signs of jaundice.
What it detects: Bilirubin is normally processed by the liver and excreted in bile. Elevated levels can point to liver dysfunction, bile duct obstruction, or increased red blood cell destruction, depending on whether the direct or indirect fraction is elevated.
Collection & prep: A standard blood draw from a vein in the arm, usually alongside other liver function tests. No special preparation is typically required.
Results:
High total/indirect – often reflects increased red blood cell breakdown or reduced liver uptake
High direct – often points to bile duct obstruction or liver processing problems
Normal – typically 2 to 17 micromoles/L (roughly 0.1–1.2 mg/dL), though ranges vary by lab
Possible complications of high bilirubin: Persistently elevated bilirubin causes jaundice (yellowing of skin and eyes) and, in newborns, can in rare severe cases lead to kernicterus; adults with abnormal results are usually evaluated further to determine the underlying liver, bile duct, or blood-related cause.
Statements made in the Clinical Manual have not been evaluated by the FDA. The products mentioned are not intended to diagnose, treat, cure or prevent any disease.
