A bilirubin test is used to help determine the increased level of bilirubin in blood. Which in turn causes jaundice, a yellowing of your skin and the sclera of your eyes. It also helps in diagnosing conditions like liver disease, hemolytic anemia, and blocked bile ducts. Bilirubin is nothing but a yellow pigment that is present in everyone’s blood and stool. It is used to break down fats in our small intestine along with the bile. Bilirubin is a product of breaking down of hemoglobin in old Red Blood Corpuscles. The one which is not attached to glucuronic acid is called as Unconjugated or Indirect Bilirubin.