Urine urobilinogen
What it measures, and what changes the number.
Urobilinogen is a colourless substance formed when gut bacteria break down bilirubin, the pigment produced from old red blood cells. Some of it is reabsorbed into the blood and a portion is passed in the urine, where this test detects it, usually with a dipstick pad.
It is read together with urine bilirubin on the same dipstick and with blood bilirubin and liver enzymes, because the pattern across these tests helps describe how bilirubin is being processed by the liver and bile ducts.
Urobilinogen breaks down when exposed to light and air, so the sample needs to be fresh and tested promptly. Output varies through the day, and some medicines and very acidic or alkaline urine can affect dipstick readings. Results are often reported semi-quantitatively. Spanish labs may print it as Urobilinógeno.
Often read alongside: Urine bilirubin, Bilirubin (total), Bilirubin (direct), ALT, AST