Test Details: Urinary reducing substances include glucose, fructose, galactose, lactose, pentose and maltose, as well as amino acids, cysteine, tyrosine, homogentisic acid, ketone bodies, ascorbic acid and many drugs. It is used as a screening test to detect inborn errors of carbohydrate metabolism. If the test results are observed to be positive, then paper chromatography for sugars and amino acids are performed on the given sample. The paper chromatography is beneficial for the detection of specific reducing substance.