Glucose in Urine: What Does It Mean if Sugar Shows Up?

Glucose in urine (glycosuria) means more sugar is passing into your urine than usual. Normally the kidneys reabsorb almost all filtered glucose and return it to the blood. The most common cause is diabetes, but pregnancy, some kidney conditions and certain medicines can also cause it, so a blood test is usually needed to find out what the result means.

This guide is for adults who have had glucose reported on a urine dipstick or urinalysis. It explains common reasons and the usual next questions. It cannot tell you why glucose is present in your case.

A urine dipstick is a quick screening check, often done as part of a routine urinalysis, at an antenatal visit or before a procedure. It shows that glucose was present in that sample. It does not show your blood sugar at that moment, how long glucose has been present or what caused it.

Glucose in urine often causes no symptoms. Arrange a prompt appointment, rather than waiting for a routine review, if it comes with signs of high blood sugar such as strong thirst, passing urine much more often, unexplained weight loss, tiredness or blurred vision.

Diabetic ketoacidosis (DKA) is a medical emergency. Get help through your local emergency number if glucose in urine comes with vomiting, stomach pain, fruity-smelling breath, confusion, marked weakness or extreme thirst, especially if you have not been diagnosed with diabetes or you take an SGLT2 inhibitor.

Blood passes through the kidneys, which filter glucose out and then reclaim it through transport proteins, one of which is called SGLT2. When blood glucose is high, more glucose is filtered than the kidneys can take back, and the excess spills into the urine. The level at which this happens is often called the renal threshold.

Because the result depends on both blood glucose and how the kidneys handle it, a normal urine glucose test does not rule out diabetes. MedlinePlus notes that urine glucose can be normal even when blood glucose is high.

Yes. Several situations can cause glycosuria while blood glucose is in the normal range:

• Renal glycosuria: an inherited kidney condition in which glucose passes into urine even though blood sugar is normal. It is uncommon.
• Fanconi syndrome and other uncommon kidney disorders, where the kidney tubules have trouble reabsorbing glucose and other substances.
• Pregnancy, when some glucose in urine is common.
• A large carbohydrate-rich meal shortly before the test, which can cause a small, temporary rise.
• SGLT2 inhibitor medicines, which deliberately increase the amount of glucose removed in urine.

Yes, as an expected effect. SGLT2 inhibitors block the kidney protein that reabsorbs glucose, so glucose comes out in urine instead. They are used for type 2 diabetes and are also used in some people with chronic kidney disease or heart failure. If you take one, a positive urine glucose test is likely and does not on its own mean your diabetes control has changed.

These medicines can rarely cause DKA in which blood glucose is only moderately raised or near normal. Seek urgent help for DKA symptoms even if your glucose reading does not look high. Never stop a prescribed medicine because of a urine result without speaking to your prescriber.

Glucose in urine is common in pregnancy, and MedlinePlus notes it may occur in up to half of pregnant women at some point. High levels over time can be a sign of gestational diabetes, which often causes no symptoms.

Screening for gestational diabetes uses blood tests, not urine. In the UK, for example, an oral glucose tolerance test is usually offered between 24 and 28 weeks to those with risk factors. Ask your midwife or doctor whether your urine result changes your testing plan.

A urine glucose test alone cannot diagnose any condition. To check for diabetes, clinicians usually use one or more blood tests.

Units and reference ranges differ between countries and labs, so compare your result with the range printed on your own report. If your A1C and glucose results point in different directions, see our guide on A1C and glucose results that do not match. If you have also had an insulin level checked, our guide on high insulin with normal glucose explains why insulin is not a standard diagnostic test.

Tell your clinician about all medicines and supplements you take. MedlinePlus notes that some medicines, vitamin C and a large meal can affect urine glucose results.

A diagnosis usually rests on the full picture: the blood results, your symptoms, your medicines and, where relevant, pregnancy. A urine result is a prompt to check, not an answer on its own.

The CDC describes the main blood tests and the levels it lists as in the diabetes range:

• A1C: average blood sugar over about two to three months. 6.5% or above is in the diabetes range.
• Fasting plasma glucose: 126 mg/dL or above is in the diabetes range.
• Oral glucose tolerance test: a 2-hour reading of 200 mg/dL or above is in the diabetes range.
• Random blood glucose: 200 mg/dL or above is in the diabetes range.

Bring the urine report, the time you gave the sample, what you had eaten, any recent blood results and a list of your medicines.

• Was this a dipstick or a laboratory urinalysis, and how much glucose was found?
• Which blood test do I need next, and do I need to fast for it?
• If my blood sugar is normal, could this be renal glycosuria, a kidney tubule problem or one of my medicines?
• If I take an SGLT2 inhibitor, should urine glucose tests be interpreted differently for me?
• If I am pregnant, does this change when I am tested for gestational diabetes?
• Which symptoms should make me contact you before my next appointment?

On SameCase, patients and verified doctors share de-identified cases. Seeing how others recorded their urine and blood results, medicines and timing can help you organise your own history and sharpen your questions.

We cannot diagnose you, and a similar case cannot explain your result. Use what you read only to prepare for a discussion with your own clinician.