Glycosuria in diabetes
High glucose (sugar) levels in the urine are common among diabetics. It is known as glycosuria. When the amount of glucose in a urine sample exceeds 25 mg/dl, a person is often said to have too much glucose in their urine. Normally, sugar is reabsorbed by the kidneys and released into the blood. Not all of it can be reabsorbed, though, because patients with diabetes can have high blood sugar levels. The urine contains the additional sugar that was discharged.
When blood sugar levels are 180 mg/dl or above, extra sugars are often only detected in the urine. For reference, a fasting or random plasma glucose test can determine whether a person has diabetes if their blood sugar level is 126 mg/dl or higher or 200 mg/dl or more, respectively.
Additionally, glycosuria can make people urinate more frequently. This is so that the bladder may fill more quickly because the increased sugar in the urine can take in more water.