Glucose, Serum (8 AM, fasting)
This test measures your blood sugar level after fasting for 8 hours. It helps check how well your body uses glucose, a key energy source.
["A fasting glucose test helps assess your risk for diabetes or other metabolic conditions."]
Key facts at a glance
- LOINC
- 45053-6
- Short code
- Glucose 8 AM SerPl-sCnc
- Synonyms
- Glucose 8 AM SerPl-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 doctor may order this test to diagnose or monitor conditions like diabetes, prediabetes, or to evaluate how your body processes glucose. It’s often done as part of a routine check or to assess symptoms like excessive thirst, fatigue, or unexplained weight changes.
What to expect before the test
You’ll need to fast (no food or drink, except water) for at least 8 hours before the test. Your doctor may provide specific instructions. Bring any medications you’re currently taking, as some may need to be adjusted or taken separately.
What happens during the test
A healthcare provider will draw a small amount of blood from a vein, usually in your arm. You may feel a slight pinch, but it’s quick and shouldn’t cause significant discomfort. The blood sample is sent to a lab for analysis.
What the results mean
Your results will show your glucose concentration in the blood. While reference ranges vary by lab, higher or lower levels than expected may signal potential health concerns that need further evaluation.
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.
Abnormally high glucose levels may indicate diabetes or insulin resistance, while persistently low levels could suggest conditions like hypoglycemia or hormonal imbalances. Your doctor will interpret results in the context of your overall health and symptoms.
Short name
Fasting morning glucose test
Frequently asked questions
Why did I need to fast for this test?
What if I forgot to fast before the test?
How long will I need to wait for my results?
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