<P> Glycosuria or glucosuria is the excretion of glucose into the urine . Ordinarily , urine contains no glucose because the kidneys are able to reabsorb all of the filtered glucose from the tubular fluid back into the bloodstream . Glycosuria is nearly always caused by elevated blood glucose levels , most commonly due to untreated diabetes mellitus . Rarely , glycosuria is due to an intrinsic problem with glucose reabsorption within the kidneys ( such as Fanconi syndrome ) , producing a condition termed renal glycosuria . Glycosuria leads to excessive water loss into the urine with resultant dehydration , a process called osmotic diuresis . </P>
why should glucose not be present in urine
because the kidneys are able to reabsorb all of the filtered glucose from the tubular fluid back into the bloodstream