The Bile Salt test is used to detect the level of bile salts in the urine or blood. Bile is a yellow-green fluid that contains water and organic molecules such as cholesterol, bile acids, and bilirubin. In humans, the two main functions of bile are digestion and absorption of fats and elimination of bile salts from the body by secretion into bile. Adult humans produce around 400 to 800 ml of bile daily. The bile is produced by the liver, and the gall bladder holds the bile produced in the liver.