What is urinary bilirubin?

Urinary bilirubin is the metabolite of red blood cell destruction. It is divided into two kinds, one is unconjugated bilirubin that has not been processed by liver, and the other is conjugated bilirubin formed by liver and glucuronic acid. Unconjugated bilirubin is insoluble in water and binds to protein in blood. It cannot pass through glomerular filtration membrane, so unconjugated bilirubin will not be detected in urine. The bilirubin that can be checked out in urine is mainly conjugated bilirubin, which has a small molecular weight and high solubility. It can be filtered by glomerulus and discharged from urine, that is, bilirubin that we check out in urine. Under normal circumstances, in our human body, the content of bilirubin combined in blood is very low, and the filtration excess is also very small. It is impossible to check bilirubin under normal circumstances. If the blood examination of urine bilirubin increased, it suggests that glomerular filtration membrane so that urine bilirubin increased. Urine bilirubin test is positive, it is mainly seen in various liver cell necrosis or obstructive jaundice caused.