bilirubiin

Bilirubin is a yellowish pigment that is made during the normal breakdown of red blood cells. Red blood cells have a lifespan of about 120 days. When they reach the end of their life, they are broken down by the body, and bilirubin is one of the byproducts.

Bilirubin travels through the bloodstream to the liver, where it is processed. In the liver, bilirubin is combined with a substance called glucuronic acid. This process makes bilirubin more soluble in water, which allows it to be excreted from the body. Bilirubin is then released into the bile, a fluid produced by the liver that aids in digestion. Bile is stored in the gallbladder and then released into the small intestine to help break down fats.

Most of the bilirubin processed by the liver is eliminated from the body in the feces, giving stool its characteristic brown color. A small amount is also excreted in the urine.

Elevated levels of bilirubin in the blood can indicate a number of medical conditions. Jaundice, a yellowing of the skin and the whites of the eyes, is a common sign of high bilirubin levels. This can occur if the liver is not functioning properly, if there is excessive breakdown of red blood cells (hemolysis), or if there is a blockage in the bile ducts that prevents bilirubin from being excreted. Common causes of elevated bilirubin include hepatitis, cirrhosis, gallstones, and certain types of anemia. Doctors can measure bilirubin levels in blood tests to help diagnose and monitor these conditions.