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Glucose in Serum (Fasting) – 24-Hour Urine Collection

Published: August 9, 2026Updated: August 16, 2026

This test measures how much glucose (sugar) appears in your urine over a 24-hour period after fasting. It helps assess how well your body controls blood sugar levels.

Quick summary

["A 24-hour urine glucose test helps detect hidden sugar in urine, often linked to diabetes or kidney issues."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
33089-4
Short code
GA from CRL.ASUM91
Synonyms
GA from CRL.ASUM91
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
us-estimated-from-crl-asum
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why This Test Is Done

Your doctor may order this test if they suspect diabetes, kidney problems, or other conditions affecting how your body processes sugar. It can also be used to monitor long-term sugar control in people with diabetes.

What to Expect Before the Test

You’ll need to collect all urine for 24 hours, starting right after midnight of one day and ending right after midnight the next. Drink plenty of water but avoid sugary drinks or medications that may affect results. Follow your doctor’s specific instructions carefully.

How the Test Works

A sample of your urine is collected and analyzed to measure the total amount of glucose excreted over the full day. The test may use methods like immunoassay or enzymatic techniques to detect glucose levels.

What the Results Mean

Results help determine if your body is efficiently managing blood sugar. Elevated levels may indicate diabetes, kidney dysfunction, or other metabolic issues. Your doctor will interpret results in the context of your overall health.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Fasting Urine Glucose

Frequently asked questions

How often should I collect urine for this test?
Collect all urine for a full 24-hour period, starting after midnight of one day and ending after midnight the next. Use a clean container and record each voided amount.
Can I eat or drink anything before the test?
Yes, but avoid sugary drinks, medications containing sugar, or foods that may affect glucose levels. Stick to plain water unless instructed otherwise by your doctor.
What if I miss a urine sample during the 24-hour period?
If you miss any urine, you’ll need to restart the collection from the next midnight. Notify your lab or doctor immediately to avoid inaccurate results.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy