bilirubin

noun

bil·​i·​ru·​bin ˌbi-li-ˈrü-bən 

ˈbi-li-ˌrü-

: a reddish-yellow water-insoluble pigment C₃₃H₃₆N₄O₆ that is formed by the breakdown of heme, is excreted in a water-soluble form by liver cells into bile, and occurs in blood and urine especially in diseased states see jaundice

Examples of bilirubin in a Sentence

Recent Examples on the Web

Your liver uses this bilirubin to make bile, a fluid that helps digest food, Shusterman said. —Alyssa Hui, Verywell Health, 12 Jan. 2024

Gilbert syndrome is a common genetic condition in that prevents the liver from properly processing bilirubin, which is made by the breakdown of red blood cells. —Anthony Robledo, USA TODAY, 1 Mar. 2024

Bacterial strains that metabolized bilirubin using bilirubin reductase all came from species that were found to belong to a single clade (the researchers informally referred to it as the bilirubin reductase clade). —Elizabeth Rayne, Ars Technica, 27 Jan. 2024

Gilbert's syndrome can cause the occasional yellowing of the skin and whites of the eyes because of too much build-up of bilirubin in the blood, according to the Cleveland Clinic. —Anthony Robledo, USA TODAY, 1 Mar. 2024

Key Takeaways Researchers have discovered that urine is yellow because of an enzyme called bilirubin reductase that’s made by certain microbes in the gut. —Alyssa Hui, Verywell Health, 12 Jan. 2024

Gut microbes then use bilirubin reductase to break down bilirubin into colorless urobilinogen, which degrades into yellowish urobilin, giving urine that infamous hue. —Elizabeth Rayne, Ars Technica, 27 Jan. 2024

Lab tests showed anemia, low blood platelets, and a buildup of bilirubin (which occurs when red blood cells break down). —Beth Mole, Ars Technica, 13 Oct. 2023

Good bacteria in your intestines break down some of the bilirubin in your bile into urobilinogen, which becomes urobilin. —Alyssa Hui, Verywell Health, 12 Jan. 2024

Word History

Etymology

Latin bilis + ruber red — more at red

First Known Use

1871, in the meaning defined above

Medical Definition

bilirubin

noun

bil·​i·​ru·​bin ˌbil-i-ˈrü-bən, ˈbil-i-ˌ 

: a reddish-yellow, crystalline, water-insoluble pigment C₃₃H₃₆N₄O₆ that is formed by the breakdown of heme, is excreted in a water-soluble conjugated form by liver cells into bile, and occurs in blood and urine especially in diseased states (such as cirrhosis, gallstones, and hemolytic anemia)

… they may become jaundiced, their skin tinged yellow by the release of the pigment bilirubin from their damaged liver.

—Larry Thompson, Discover