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Glucose in Serum (24-hour Profile)

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

This test measures your blood sugar levels over a 24-hour period using a sample of your serum, helping doctors assess how your body manages glucose over time.

Quick summary

["Understanding how your body handles blood sugar throughout the day is key to managing conditions like diabetes."]

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

Key facts at a glance

LOINC
14147-3
Short code
GH 1.5h p chal SerPl-mCnc
Synonyms
GH 1.5h p chal SerPl-mCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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

A 24-hour glucose profile is often recommended if you have symptoms of diabetes, prediabetes, or if your blood sugar levels fluctuate unpredictably. It may also be used to evaluate how well your current diabetes treatment plan is working or to diagnose conditions like reactive hypoglycemia.

What to Expect Before the Test

You’ll need to fast for 12 hours before your first blood draw, but you can drink water. Your doctor or lab technician will collect serum samples at regular intervals over 24 hours. Some tests may require you to keep a food and activity diary to track patterns.

What the Results Mean

The results will show your blood sugar levels at multiple points during the day, helping identify patterns such as highs or lows. Normal results may vary depending on your health status, but this test helps pinpoint whether your glucose levels are consistently high, low, or unstable.

Common Conditions Monitored

This test is critical for diagnosing and managing diabetes, prediabetes, and conditions like reactive hypoglycemia. It can also help determine if your current medications or lifestyle changes are effective in controlling blood sugar levels.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Frequently asked questions

How often should I have this test if I have diabetes?
Your doctor will determine the frequency based on your specific needs, but typically, a 24-hour glucose profile is done annually or more often if your blood sugar is unstable or if you’re adjusting treatments.
Can I eat or drink anything before the first blood draw?
No, you must fast for 12 hours before the first blood draw, but you can drink water. Avoid caffeine or sugary drinks to keep results accurate.
What if I miss a scheduled blood draw?
If you miss a sample, inform your lab technician immediately. Missing samples can affect the accuracy of your 24-hour profile results, so follow your doctor’s instructions to reschedule or adjust your testing plan.
  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