Urine oligosaccharides are evaluated in patients suspected of having one of the oligosaccharidoses, a group of lysosmal storage disorders including mannosidosis, fucosidosis and sialidosis. Other disorders detected by this test include GMI-gangliosidosis and Sandhoff disease. Urinary oligosaccharides are fractionated using thin-layer chromatography, and abnormal bands are visualized following staining with orcinol. Additional staining with resorcinol may also be performed for confirmation of sialic acid-containing oligosaccharides. Clinical history should be provided to the laboratory for optimal interpretation of results.