Fasting Plasma Glucose (24-Hour Average Concentration)
This test measures the average level of glucose (sugar) in your blood over a 24-hour period, using a sample of plasma taken after fasting. It helps assess long-term blood sugar control, often linked to diabetes management.
This test helps doctors check how well your body regulates blood sugar over time.
Key facts at a glance
- LOINC
- 79264-8
- Short code
- Glucose Ovrngt Dwell DiafP-sCnc
- Synonyms
- Glucose Ovrngt Dwell DiafP-sCnc
- 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?
Your healthcare provider may order this test if you have symptoms of diabetes (like frequent urination, excessive thirst, or fatigue), if you have a family history of diabetes, or if you’re at risk due to other health conditions. It’s also used to monitor long-term blood sugar levels in people already diagnosed with diabetes.
How Is the Sample Collected?
You’ll fast (not eat or drink except water) for 8–12 hours before the test. A blood sample is drawn from a vein, usually in your arm, and sent to a lab for processing. The plasma portion is analyzed to measure glucose concentration over time.
What Does the Result Mean?
Results are typically reported as an average concentration of glucose in your plasma. While exact reference ranges vary by lab, higher-than-normal averages may indicate poor blood sugar control, which could signal diabetes or prediabetes. Your doctor will interpret results in the context of your overall health.
What Are Common Causes of Abnormal Results?
Factors like stress, illness, certain medications (e.g., steroids), or recent infections can temporarily affect glucose levels. If your results are abnormal, your doctor may recommend further testing or adjustments to your treatment plan.
Reference range
Fasting: 70-100 mg/dLN/A
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.
This test is critical for diagnosing and managing diabetes because chronic high blood sugar can lead to serious complications, such as nerve damage, kidney disease, or heart problems. It helps doctors track progress with treatments like medication or lifestyle changes.
Short name
Fasting Plasma Glucose Profile
Frequently asked questions
Why did my doctor ask for this test?
What should I do if my fasting plasma glucose is higher than expected?
Can I eat or drink anything before this test?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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