What is a 24-Hour Urine Glucose test?
This test measures the total amount of glucose (sugar) in all the urine you produce over a 24-hour period.
Glucose is the body's main source of energy. Normally, your kidneys filter glucose from your blood and then reabsorb almost all of it back into the bloodstream. As a result, only a very small amount of glucose, or sometimes none, is normally found in urine.
When the level of glucose in your blood becomes higher than the kidneys can reabsorb, glucose can begin to appear in the urine. Measuring glucose over a complete 24-hour period can provide information about glucose metabolism and how much glucose is being lost through the kidneys.
A 24-hour urine glucose test can provide useful information when evaluating diabetes, persistent glucose in the urine, and certain kidney or metabolic disorders.
Other names: 24-hour urine glucose, urinary glucose, urine glucose, glucosuria test
What is it used for?
A 24-hour urine glucose test may be used to help:
Evaluate diabetes
Glucose in the urine can occur when blood glucose levels are sufficiently elevated. The test may provide additional information about glucose control, although blood glucose and HbA1c are generally preferred for diagnosing and monitoring diabetes.
Investigate glucose in the urine
If glucose is detected in a urine sample, a 24-hour collection may help determine the total amount of glucose being excreted.
Evaluate renal glycosuria
Sometimes glucose can appear in the urine even when blood glucose is normal. This can occur when the kidneys do not reabsorb glucose normally, a condition sometimes called renal glycosuria.
Investigate certain metabolic or kidney disorders
The test may occasionally be used as part of an evaluation for conditions affecting glucose handling by the kidneys or body.
Why do I need a 24-Hour Urine Glucose test?
You may need this test if:
Glucose has been detected in your urine.
Your healthcare provider wants to investigate persistent glucosuria.
You have diabetes and your provider needs additional information about glucose loss in urine.
Glucose is present in urine despite having a normal or near-normal blood glucose level.
Your provider suspects a disorder affecting the kidneys' ability to reabsorb glucose.
You have other findings suggesting a metabolic or kidney disorder.
What happens during a 24-Hour Urine Glucose test?
This test requires you to collect all of your urine for 24 hours in a special container provided by your healthcare provider or laboratory.
The collection generally includes the following steps:
At the beginning of the collection period, urinate in the toilet as usual. Do not collect this first urine. Record the time.
For the next 24 hours, collect all urine in the provided container.
Store the container as instructed, usually refrigerated or in a cool place during the collection period.
Exactly 24 hours after starting the test, urinate one final time and include this urine in the container.
Return the completed collection to your healthcare provider or laboratory as instructed.
It is important to collect all urine produced during the 24-hour period. Missing a urine sample can make the result inaccurate.
Will I need to do anything to prepare for the test?
Usually, no fasting is required for a 24-hour urine glucose test.
Your healthcare provider may give you specific instructions regarding your diet, fluid intake, or medications.
Do not change your diet or stop taking prescribed medicines unless your healthcare provider tells you to do so.
Are there any risks to the test?
There are no known medical risks from collecting a 24-hour urine sample.
The main concern is accidentally missing part of the urine collection, which can affect the accuracy of the result.
What do the results mean?
The result represents the total amount of glucose excreted in the urine during 24 hours and may be reported as mg/24 hours, g/24 hours, or mmol/24 hours, depending on the laboratory.
The meaning of your result depends on your blood glucose level, kidney function, medications, diet, and other laboratory findings.
A high level of 24-Hour Urine Glucose
A high urine glucose level means that more glucose than expected is being lost through the kidneys.
Possible causes include:
Diabetes mellitus
High blood glucose levels
Pregnancy-related changes in glucose handling
Renal glycosuria
Certain kidney disorders affecting glucose reabsorption
Some medications, such as SGLT2 inhibitors, which intentionally increase glucose excretion in urine
A low or normal level of 24-Hour Urine Glucose
A normal or very low urine glucose level is generally expected when blood glucose levels are within the normal range and the kidneys are reabsorbing glucose normally.
However, a normal urine glucose result does not rule out diabetes. Blood glucose testing and HbA1c are more appropriate tests for diagnosing and monitoring diabetes.
Important note
A 24-hour urine glucose result should not be interpreted by itself. It is usually evaluated together with blood glucose, HbA1c, kidney function, urinalysis, medications, and other clinical findings.
The amount of glucose in urine depends strongly on the blood glucose concentration and the kidney's glucose reabsorption threshold. Therefore, urine glucose testing is generally not a replacement for blood glucose or HbA1c testing when evaluating diabetes.
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