What Is Glycosuria?

Medically Reviewed by Dan Brennan, MD on July 07, 2023
4 min read

Glycosuria occurs in some conditions like diabetes. Some people don’t know they have glycosuria until they have a urine test done. 

Glycosuria happens when you have glucose, or other sugars like lactose, fructose, or galactose, in your urine. This is sometimes also called glucosuria.‌

Normally, your body eliminates glucose in your urine when your blood sugar levels are too high. In healthy people, your kidneys filter the glucose and reabsorb most of it back into your blood. ‌

Your body carefully controls glucose levels to maintain a steady balance. Too much glucose can damage your organs and nerves, but your body does need enough sugar for energy. ‌

A small amount of glucose in your urine is normal. If a random urine sample shows more than 0.25mg/ml, this is considered glycosuria and can be caused by too high blood glucose levels, a problem with your kidney filters, or both.

There are three main causes of glycosuria: 

  • Conditions with problems using or making the hormone insulin
  • Conditions with the kidney where the tubules are damaged, or other kidney defects
  • Eating more sugars than the body can process at once

Diabetes, called diabetes mellitus, is a condition where your body can’t make enough insulin or use insulin properly. Insulin is a hormone that regulates how much glucose is in your blood. ‌

There are two types of diabetes:‌

Type 1 diabetes. This type is an autoimmune disease where your immune system destroys beta cells in your pancreas that make insulin. Type 1 diabetes usually develops in childhood or teenage years. ‌

Type 2 diabetes. In this type, your body becomes resistant to insulin and doesn’t respond to the hormone, which causes problems using glucose. Obesity and weight gain are major factors in getting type 2 diabetes. It often develops later in life, but children who have obesity can also get type 2 diabetes.  

Diabetes causes glycosuria because there either isn’t enough insulin, or your body can’t use what's available. WIthout insulin, blood glucose levels become too high, and your kidneys can’t filter and reabsorb it. Your body gets rid of the excess through your urine

Gestational diabetes is a type of diabetes that happens during pregnancy. Your body needs a lot of energy as your baby grows, but sometimes it can’t keep up with demand and doesn't make enough insulin.‌

Without the insulin, you will have too high sugar levels, and it will show up in your urine. ‌

High blood sugar levels during pregnancy can cause problems for you and your baby:

  • Your baby grows too big, and you need a C section
  • High blood pressure
  • High blood sugar in your baby
  • Risk of heart disease and type 2 diabetes after your pregnancy is over‌

Your doctor might do in-office urine tests at your regular prenatal visits to check for glycosuria. You will have another test around the 24 to 28 week mark where you drink a glucose drink and have your blood taken. Your doctor might do the blood test earlier if your urine tests show high glycosuria.

Renal glycosuria is a rare inherited condition where your body eliminates sugar in your urine even though your blood levels are normal. In this condition, you don’t have too much glucose but your body gets rid of it anyway. 

It is caused by gene changes that lead to defects in your kidney tubules where glucose is absorbed. Renal glycosuria usually doesn’t have any symptoms and doesn’t need treatment.

Fanconi syndrome is a general term for a defect in your kidneys that causes problems absorbing glucose. This can be caused by:

It can also be caused by some genetic conditions, including:

  • Wilson disease
  • Dent disease
  • Lowe syndrome
  • Cystinosis

Alimentary glycosuria can happen when you eat lots of carbohydrates at a meal. Blood glucose levels become abnormally high after eating, the glucose is passed into your urine, and levels take longer to normalize. 

This is a temporary condition in healthy people, but it can be a sign of renal glycosuria. It also happens in people with diabetes

You might not know you have glycosuria until your urine is tested. Some types like renal glycosuria and gestational glycosuria don’t cause any symptoms.‌

Over time, if it’s not treated, it can cause some symptoms, including:

  • Tiredness
  • Peeing a lot
  • Feeling very thirsty
  • Weight loss
  • Feeling sick

The treatment for glycosuria depends on the cause. Diabetes is best managed with lifestyle changes and medications. 

Treatments can include:

Not everyone with glycosuria is unwell or needs treatment. If you have signs of blood sugar problems, talk to your doctor.