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Glucose in Serum or Plasma (24-Hour Average)

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

This test measures your average blood glucose level over a 24-hour period, using a sample of your blood serum or plasma. It helps assess long-term blood sugar control.

Quick summary

["This test provides insight into how well your body manages blood sugar over time, useful for diabetes management."]

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

Key facts at a glance

LOINC
109729-4
Short code
Glucose Msmt DiafP
Synonyms
Glucose Msmt DiafP
Category
glucose
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
70
Ref high
100
Critical range
50 N/A – 400 N/A
Fasting
true
Population
adult
Sex
all
Age range
18–65 years
CPT
82947
SNOMED
260395008
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 Is This Test Done?

Doctors may order a 24-hour average glucose test to monitor long-term blood sugar levels in people with diabetes. It helps track whether your current treatment plan is effective and identifies trends that might affect your health.

How Is the Test Performed?

A healthcare provider will collect a blood sample from a vein in your arm. The sample is processed to measure glucose levels over time, often using a specialized method like continuous glucose monitoring data or repeated measurements.

What Does the Test Result Mean?

Results are typically reported as an average value over 24 hours. While exact reference ranges vary by lab, higher-than-normal levels may indicate poor blood sugar control, while lower-than-normal levels could suggest hypoglycemia or other conditions.

Common Causes of Abnormal Results

Elevated levels may be due to diabetes, poor insulin function, or certain medications. Lower-than-normal levels can result from excessive insulin, certain foods, or medical conditions affecting blood sugar regulation.

Reference range

Fasting: 70-100 mg/dLN/A

Specimen: serum

Fasting for 8-12 hours required. Water is permitted. Avoid chewing gum and smoking before the test.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

24-Hour Average Glucose

Frequently asked questions

What does a 24-hour average glucose test involve?
This test involves measuring your blood glucose levels over a full day using a sample of your blood serum or plasma. It often relies on data from continuous glucose monitoring or multiple blood draws to calculate your average level.
How often should I get this test?
Your doctor will determine the frequency based on your health needs, diabetes management plan, or other medical conditions. Regular testing may be recommended every few months or annually, depending on your situation.
Can lifestyle changes affect this test result?
Yes, lifestyle factors like diet, exercise, and medication use can impact your blood sugar levels. Following a balanced diet, staying active, and managing medications as prescribed can help improve your test results over time.
  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