Serum or plasma concentration of bilirubin (total)

Why Your Bilirubin Levels Matter

High bilirubin levels can indicate problems with your liver, bile ducts, or red blood cells. For example, jaundice (yellowing of the skin and eyes) often appears when bilirubin builds up too quickly. Low levels may suggest certain liver conditions or blood disorders that need further evaluation.

What Causes Bilirubin Levels to Change?

Bilirubin can rise due to conditions like hemolysis (red blood cell destruction), liver disease (such as hepatitis or cirrhosis), or blockages in the bile ducts. It can also drop if your liver isn’t processing bilirubin efficiently or if certain medications affect its metabolism.

When You Might Need This Test

Your doctor may order this test if you have symptoms like jaundice, unexplained fatigue, dark urine, pale stools, or signs of liver problems. It’s also used during pregnancy to check for hemolytic disease in newborns or to monitor liver health in chronic conditions.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to fast for 8–12 hours before the test if your lab uses a fasting protocol. Bring any medications or supplements you’re taking, as they could affect results.