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Glucose, Plasma (24-Hour Average)

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

This test measures the average blood sugar level over a 24-hour period, using plasma from a blood sample. It helps assess long-term blood glucose control, often linked to diabetes management.

Quick summary

This test gives insight into how well your body manages blood sugar over time.

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

Key facts at a glance

LOINC
1527-1
Short code
Glucose 30M p 75 g Glc PO SerPl-mCnc
Synonyms
Glucose 30M p 75 g Glc PO SerPl-mCnc
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 This Test Is Done

Doctors may order this test to monitor blood sugar levels in people with diabetes or prediabetes. It’s particularly useful for evaluating how well medications or lifestyle changes are controlling glucose over time, rather than just checking levels at one point in time.

How the Test Works

A blood sample is collected, typically from a vein in your arm. The plasma portion is analyzed to determine the average glucose concentration over 24 hours, often using an enzymatic method to measure glucose levels.

Sample Collection and Preparation

Plasma is separated from whole blood in the lab and tested for glucose concentration. This test does not require fasting unless specified by your healthcare provider.

What to Expect Before the Test

No special preparation is needed, but inform your healthcare provider if you’re taking medications that could affect blood sugar, such as insulin or oral diabetes medications.

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.

A 24-hour average glucose test provides a more accurate picture of long-term blood sugar control compared to single-point measurements. It helps identify trends in hyperglycemia (high blood sugar) or hypoglycemia (low blood sugar) that may not be apparent from routine blood tests. This can guide treatment adjustments, especially in people with diabetes.

Short name

24-Hour Average Plasma Glucose

Frequently asked questions

What does a high or low result mean?
A high average glucose level may indicate poor diabetes management, insulin resistance, or other metabolic conditions. A low average level could suggest over-treatment with insulin or other glucose-lowering medications. Your doctor will interpret results in the context of your overall health and treatment plan.
How often should I get this test?
Your doctor will determine the frequency based on your medical needs. Typically, it may be recommended every few months for people with diabetes to track progress with treatment.
Can I eat or drink before this test?
Unless instructed otherwise, you can eat and drink normally before this test. However, if your doctor specifies fasting requirements, follow those guidelines to ensure 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 16, 2026. · Read our editorial policy