Glycosuria happens when you pass blood sugar (blood glucose) into your urine.

Normally, your kidneys absorb blood sugar back into your blood vessels from any liquid that passes through them. With glycosuria, your kidneys may not take enough blood sugar out of your urine before it passes out of your body.

This often happens because you have an abnormally high level of glucose in your blood (hyperglycemia). Sometimes, glycosuria can develop even if you have normal or low blood sugar levels. In these situations, it’s known as renal glycosuria.

Read on to find out how to recognize glycosuria, how it’s diagnosed, and more.

Glycosuria is typically caused by an underlying condition that affects your blood sugar level, such as diabetes. Type 2 diabetes is the most common cause of glycosuria.

If you have this condition, your body’s insulin doesn’t work properly in one of two ways. In some cases, insulin can’t transport blood sugar into your body’s cells effectively. This can cause blood sugar to be passed out in your urine instead.

In other cases, your body doesn’t make enough insulin to balance your blood sugar levels. Any excess blood sugar is passed out through your urine.

Glycosuria can also happen if you develop gestational diabetes during pregnancy. This type of diabetes happens when hormones that come from your baby’s placenta prevent the insulin in your body from properly controlling your blood sugar. This can cause your blood sugar to become abnormally high. Gestational diabetes is preventable, though. Here’s how.

Renal glycosuria is a much rarer form of glycosuria. This happens when your kidney’s renal tubules — the parts of the kidneys that act as filters in your urinary system — don’t filter blood sugar out of your urine properly. This condition is often caused by a mutation in a specific gene.

Unlike glycosuria that happens because of type 2 diabetes, renal glycosuria isn’t necessarily caused by your overall health or lifestyle choices.

There aren’t any immediately obvious symptoms of glycosuria. In fact, many people experience glycosuria for years and never notice any symptoms.

But if left untreated, glycosuria can cause you to:

  • feel extremely thirsty or dehydrated
  • feel extremely hungry
  • urinate more than usual
  • urinate accidentally

If your glycosuria is a sign of type 2 diabetes, you may also experience:

  • unexplained weight loss
  • fatigue
  • trouble seeing
  • slow-healing cuts, sores, or other injuries
  • skin darkening in the folds of your neck, armpits, or other areas

Glycosuria resulting from gestational diabetes typically doesn’t cause any additional symptoms.

If you begin experiencing any unusual symptoms, see your doctor.

Glycosuria can be diagnosed in a number of ways, but urinalysis is the most common approach.

For this test, your doctor will ask you to urinate on a test strip to be sent off to a lab for testing. The lab technician will be able to determine whether your urine glucose levels suggest glycosuria. You may have glycosuria if the amount of glucose in your urine is higher than 180 milligrams per deciliter (mg/dL) in a single day.

Your doctor may also order blood tests to check your blood sugar. Normal blood sugar levels are usually between 70–140 mg/dL depending on whether you’ve eaten recently or whether you have diabetes.

If your blood sugar levels are high and diabetes hasn’t been diagnosed previously, your doctor will likely perform a glycated hemoglobin (A1C) test. This blood test provides information about your blood sugar levels for the past few months.

Glycosuria isn’t a cause for concern on its own. No treatment is needed if there isn’t an underlying condition that’s causing you to pass high amounts of glucose in your urine.

If a condition like diabetes is causing your glycosuria, your doctor will work with you to develop a treatment plan.

Possible treatment and management options include:

  • Getting at least 30 minutes of physical activity every day.
  • Developing a diet plan that provides you with enough nutrients while also decreasing sugar or fats intake. This may mean eating more whole grains, vegetables, and fruits.
  • Taking medications to help your body use insulin more effectively. These can include metformin (Glumetza), which allows your body to respond better to insulin, or sulfonylureas (Glyburid), which helps your body make more insulin.
  • Keeping track of your blood sugar levels so that you can better understand how your body reacts to certain foods, activities, or therapies.

Although type 2 diabetes is a lifelong condition, gestational diabetes typically resolves after childbirth. But developing it raises your risk of type 2 diabetes later in life.

The outlook for glycosuria without an associated condition is good. If you have renal glycosuria, you may go on to develop diabetes if you don’t follow a treatment plan to help manage your kidneys’ inability to properly filter glucose.

If your glycosuria is caused by diabetes, your outlook improves if you maintain a consistent treatment or management plan. Eating well, exercising every day, and taking any medications that your doctor prescribes can keep you from experiencing any additional complications.

You can’t prevent genetic conditions like renal glycosuria. But you can prevent glycosuria — and conditions like diabetes — through certain lifestyle choices.