Bilirubin - Definition

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Bilirubin comes from the breakdown of the hemoglobin in senescent red blood cells in the spleen. It is a yellow pigment responsible for the color of urine. It circulates in the blood linked to a protein, albumin, then is captured in the liver and is excreted in the bile. Jaundice, or yellowing, gives the skin a yellowish color, and is caused by a buildup of bilirubin in the blood. Too high a rate or a sudden increase of bilirubin in the blood may suggest an abnormal destruction of red blood cells, hepatitis, or cirrhosis of the liver. Bilirubin mainly exists in two forms: the so-called free bilirubin is toxic and is transformed by the liver into so-called conjugated bilirubin which is then eliminated through the urine and fecal matter.