A bilirubin test measures the amount of bilirubin in a blood sample. Bilirubin is a brownish yellow substance found in bile. It is produced when the liver breaks down old red blood cells. Bilirubin is then removed from the body through the stool (feces) and gives stool its normal color. Increased production or decreased excretion of Bilirubin results in Jaundice. The sum of Bilirubin-Direct and Bilirubin-Indirect equals total bilirubin (BRT), which is usually measured as part of a routine chemistry profile and in liver profiles.