Bilirubin (total)

This is the harmonised UK adult upper limit; some labs print up to 24, and newborns have a completely different range.

Bilirubin is the yellow pigment made when old red blood cells are broken down. The liver processes it and passes it into bile, and from there into the gut. Total bilirubin counts both the unprocessed form arriving at the liver and the processed form leaving it. The test measures the amount in a blood sample.

It is part of the standard liver panel. Doctors use it when someone looks yellow (jaundice), when looking into liver, gallbladder or bile duct problems, and when checking whether red blood cells are breaking down faster than usual.

• Gilbert's syndrome, a harmless inherited trait present in around one in twenty people in the general population, particularly after fasting or illness
• Blockage of the bile ducts, including gallstones
• Liver conditions such as hepatitis, fatty liver or alcohol-related damage
• Faster breakdown of red blood cells
• Some medicines, including certain antibiotics and HIV medicines
• Fasting, illness or hard exercise, especially in people with Gilbert's

• Some medicines that speed up liver processing, such as certain epilepsy medicines
• Smoking, by a small amount
• It has no meaningful lower limit

• Gilbert's syndrome is the commonest reason for a value a little above range and is harmless in the general population
• Fasting before the test raises it, particularly in Gilbert's
• A sample left in bright light loses bilirubin and reads lower

Fasting is not needed and a long fast raises the value. Total bilirubin is often followed by a split into conjugated and unconjugated forms when it is raised.

Written by a UK consultant physician. Typical UK adult reference ranges; your laboratory's own printed range takes precedence.