Test guide
Bilirubin Blood Test
A bilirubin blood test measures the levels of bilirubin in your blood. Bilirubin is a yellowish substance made during your body's normal process of breaking down old red blood cells. Bilirubin is found in bile, a fluid your liver makes to help you digest food.
What it is for
A bilirubin blood test may be used to check the health of your liver, look for the cause of jaundice, or determine how well a treatment is working. The test is also commonly used to help diagnose newborn jaundice. Many healthy babies get jaundice because their livers haven't developed enough to get rid of the bilirubin. Newborn jaundice is usually not harmful and clears up within a few weeks. But in some cases, high bilirubin levels can lead to brain damage, so infants are often tested as a precaution. Source: MedlinePlus, National Library of Medicine. Medical test information is public domain. Source identity and definition checked automatically on 2026-10-18. No individual clinical interpretation or human reviewer is asserted.
Limitations
Reference intervals and interpretation depend on the laboratory, specimen, method and clinical context. This source definition is educational information; it does not establish a diagnosis, product approval or suitability for an individual.
Also known as
- Total serum bilirubin, TSB total bilirubin, TBIL neonatal bilirubin, direct bilirubin, conjugated bilirubin, indirect bilirubin, unconjugated bilirubin
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