Urine test for sugar (glucose)

Sugar (glucose) normally is not found in urine. However, when blood sugar levels rise well above a safe level-which occurs in diabetes-the kidneys often release some of the excess sugar from the blood into the urine. In pregnant women, the kidneys sometimes release sugar into the urine even when blood sugar levels are within a safe range.

You can test urine for sugar by using plastic strips you can buy at a pharmacy. You dip a strip into a urine sample. The strip changes color to show how much sugar is in the sample. You compare the resulting color to a chart of colors; each color indicates a level of glucose.

Urine testing for sugar is not an accurate way to measure how much sugar is in your blood; therefore, most doctors no longer recommend it for people with diabetes. A sample of urine often is stored in your bladder for several hours before you test it. Also, because sugar does not show up in urine until it is much higher than normal in the bloodstream (180 mg/dL), urine cannot be used to check for slightly high or low blood sugar levels.