Urine bilirubin
What it measures, and what changes the number.
Bilirubin is a yellow pigment produced when old red blood cells are broken down. The liver converts it into a water-soluble conjugated form, and only this conjugated form can pass into urine. This test, usually a dipstick part of a routine urinalysis, checks whether bilirubin is present in urine.
It is commonly read with urine urobilinogen, a related breakdown product, and with blood tests such as total and direct bilirubin, ALT and ALP, which describe liver and bile duct function more directly.
Bilirubin breaks down in light and at room temperature, so a fresh, protected sample gives the most reliable reading. Vitamin C and some medicines can interfere with dipstick chemistry. Results are often reported as negative or graded positive rather than as a measured amount. Reports may simply say Bilirrubina under the urine section.
Often read alongside: Urine urobilinogen, Bilirubin (total), Bilirubin (direct), ALT, ALP