Normally, small amounts of conjugated bilirubin, regurgitate back from the bile duct and enter the blood stream, so small amounts of conjugated bilirubin can be found in the plasma. Since conjugated bilirubin is not bound to protein, it is easily filtered through the glomerulus and excreted in the urine whenever the plasma level is increased. Normally, no detectable amount of bilirubin (sometimes referred to as “bile”) is found in the urine.