Test Details: The test is specific for glucose. This test may be used to determine whether the reducing substance found in urine is glucose. Glucosuria occurs when the renal threshold for glucose is exceeded (typically >180 mg/dL); this is most commonly, although not exclusively, seen in diabetes. However, if the urine glucose is high and the patient is not known to have diabetes mellitus, more specific testing should be considered (fasting blood glucose and/or glycosylated hemoglobin).