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