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Glucose in Serum (24-Hour Quantitative Measurement)

Published: August 9, 2026Updated: August 17, 2026

This test measures your blood glucose levels over a 24-hour period to help assess how your body manages sugar (glucose) throughout the day.

Quick summary

["Understanding how your body regulates blood sugar over time can help identify risks for diabetes or other metabolic conditions."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
2355-6
Short code
G6Pas Tiss-cCnt
Synonyms
G6Pas Tiss-cCnt
Category
glucose
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
10
Ref high
40
Critical range
— – 500 N/A
Fasting
true
Population
adult
Sex
all
Age range
18–65 years
CPT
84484
SNOMED
302774002
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 healthcare provider may order this test if you have symptoms like frequent urination, extreme thirst, fatigue, or unexplained weight changes. It’s also used in diagnosing or monitoring conditions like diabetes, prediabetes, or metabolic disorders.

What to Expect Before the Test

You’ll typically provide a blood sample from a vein (usually in the arm) on two separate days, spaced 24 hours apart. Fast before each draw if instructed, as fasting may be required to ensure accurate results.

How the Test Works

Blood samples are collected at set intervals (e.g., morning and evening) to track glucose levels continuously. The test measures the concentration of glucose in your serum, which is then analyzed to create a profile of your blood sugar trends.

What the Results Mean

Results help identify patterns in your glucose levels, such as spikes or drops, which can indicate how well your body responds to insulin or other factors affecting blood sugar. Abnormal patterns may signal diabetes, insulin resistance, or other metabolic issues.

Reference range

Adult: 10-40 U/LN/A

Specimen: serum

No special preparation required. Avoid fatty meals before the test if possible.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

24-Hour Serum Glucose Profile

Frequently asked questions

How often should I get this test?
This test is usually done once or twice a year if you have diabetes or prediabetes, or as recommended by your doctor. If you’re healthy, it may not be routinely recommended unless you have risk factors like obesity, a family history of diabetes, or high blood pressure.
What if my results are outside normal ranges?
If your glucose levels show unusual patterns, your doctor may recommend lifestyle changes (like diet, exercise, or medication) to help manage your blood sugar. They may also order additional tests to check for conditions like diabetes or hypoglycemia.
Can I eat or drink before the blood draw?
Yes, but follow your doctor’s instructions carefully. Some tests require fasting (no food or drink except water) for a few hours before drawing blood to get accurate 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 17, 2026. · Read our editorial policy