In renal glucosuria (glycosuria), glucose (sugar) is excreted in the urine, despite normal or low glucose levels in the blood.

Normally, the body excretes glucose in the urine only when glucose levels in the blood are very high. In most healthy people, glucose that is filtered from the blood by the kidneys is completely reabsorbed back into the blood. In people with renal glucosuria, glucose may be excreted in the urine despite normal or low levels of glucose in the blood. This happens because of a defect in the tubular cells that decreases the reabsorption of glucose. Renal glucosuria may be a hereditary condition.

Renal glucosuria has no symptoms or serious consequences. A doctor makes the diagnosis when a routine urine test detects glucose in the urine even though glucose levels in the blood are normal. In a small number of people, renal glucosuria may be an early sign of diabetes mellitus. No treatment is needed.

Last full review/revision December 2006 by Peter C. Brazy, MD