Reducing substances are not normally present in urine and faeces. This test will detect the presence of reducing sugars, eg glucose, lactose, maltose, fructose and galactose. Urine for reducing substances test is a screening test that is done to detect inborn errors of carbohydrate metabolism. This test helps to screen for disorders with increased excretion of glucose, fructose, galactose, succinylpurines, disaccharides, and oligosaccharides. The Urine for reducing substances test is done To detect glucosuria To detect non-glucose reducing substances To screen for galactosemia galactosuria.