Glycosuria is the presence of glucose in the urine, which may indicate certain health conditions such as diabetes or kidney disease.
Normally, the kidneys filter glucose from the blood and reabsorb it, preventing it from being eliminated in the urine. However, when blood glucose levels are very high, the kidneys cannot reabsorb all the glucose, leading to its excretion through the urine.
Whenever glucose is found in a urine test, it is important to consult a primary care doctor, nephrologist, or endocrinologist to determine the cause and start appropriate treatment.
Symptoms of glucose in the urine
The main symptoms of glycosuria include:
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Frequent urination
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Excessive thirst
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Fatigue
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Unexplained weight loss
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Recurrent urinary tract infections
People with high blood glucose levels or undiagnosed diabetes mellitus may also experience increased appetite, as the body is unable to use glucose properly.
In some cases, diabetic ketoacidosis can develop. This is a medical emergency marked by extremely high and prolonged blood sugar levels.
How to confirm the diagnosis
In addition to a urine test, the doctor may order a blood test to measure glucose levels.
If the levels are high, additional tests may be recommended to confirm diabetes, such as a glycated hemoglobin (A1C) test.
If blood glucose levels are normal and glycosuria is still present, this may suggest kidney dysfunction. In such cases, the doctor may request tests to assess kidney function, including a 24-hour urine collection, creatinine clearance, and glomerular filtration rate (GFR).
Normal glucose levels in urine
In a urine test, normal glucose levels are typically zero or only a trace amount, meaning there is no detectable glucose in the urine.
However, some laboratory tests can measure the exact amount of glucose present.
When results show more than 0.25 mg/mL of glucose, glycosuria is considered present. It’s important to note that this reference value can vary slightly between laboratories.
Main causes of glycosuria
The presence of glucose in the urine is most often caused by:
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Diabetes mellitus
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Gestational diabetes
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Cushing’s syndrome or Fanconi syndrome
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Cystinosis
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Chronic kidney failure
The main difference between the most common causes and kidney-related conditions is that in cases of glycosuria caused by diabetes or pancreatic dysfunction, blood glucose levels are also elevated.
In contrast, in renal glycosuria, which results from kidney problems, blood glucose levels usually remain normal.
Treatment options
Treatment for glycosuria should always be guided by a doctor, whether a primary care physician, nephrologist, or endocrinologist, and it varies depending on the underlying cause.
When glycosuria is related to high blood sugar levels, the endocrinologist may recommend lifestyle changes, such as following a balanced diet and exercising regularly, along with medication.
In these cases, insulin or oral hypoglycemic medications like metformin may be prescribed.
When glycosuria is caused by kidney problems, treatment should be supervised by a nephrologist to determine if any specific kidney condition requires targeted therapy.
In many cases, renal glycosuria does not require active treatment. The doctor may recommend regular urine and blood tests to monitor its progression, staying well hydrated with electrolyte solutions, and avoiding nephrotoxic medications.