Although glucose is the sugar most commonly tested for in urine, normal human urine can contain small amounts of galactose, lactose, fructose, xylose, and other pentoses. Galactosuria, an abnormal amount of galactose in the urine, occurs in infants with a congenital metabolic defect. Lactose may be found in the urine of nursing women and during late pregnancy. All of these sugars, including glucose, are reducing substances.
