orange-yellow pigment of bile, the green fluid that
aids in digestion and that is secreted by the liver.
Bilirubin is formed mainly by hemoglobin breakdown
at the end of red cell life and eventually most
of it leaves the body in the feces. Two types are
in the blood. Water insoluble or unconjugated bilirubin
refers to the pigment before it reaches the liver.
In the liver it is converted to the water-soluble
or conjugated bilirubin which is excreted into the
bile. Blood tests for total bilirubin measure both
unconjugated and conjugated bilirubin, and are performed
to evaluate jaundice. anemia, various liver diseases
(including hepatitis), and impaired bile excretion.