Glucose, Serum or Plasma Concentration (Quantitative)
This test measures the amount of glucose (sugar) in your blood, typically drawn from a vein or collected in a tube. It helps assess blood sugar levels and identify conditions like diabetes.
["Glucose levels help monitor blood sugar health and diabetes management."]
Key facts at a glance
- LOINC
- 14764-5
- Short code
- Glucose 3h p 100 g Glc PO SerPl-sCnc
- Synonyms
- Glucose 3h p 100 g Glc PO 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?
Doctors order glucose tests to check for high or low blood sugar, diagnose diabetes, evaluate symptoms like excessive thirst or fatigue, or monitor treatment progress. It may also be used during pregnancy (gestational diabetes) or before surgeries.
What to Expect Before the Test
No special preparation is usually needed, but you may be asked to fast (not eat) for 8–12 hours before the test if it’s a fasting glucose check. Wear comfortable clothing for vein access.
How the Test Works
A healthcare provider will insert a small needle into your arm to draw blood. The sample is sent to a lab where it’s analyzed to measure glucose concentration using an enzymatic method.
What the Results Mean
Results are compared to general reference ranges, but your doctor will interpret them in the context of your health history and symptoms. Abnormal results may trigger further testing or lifestyle adjustments.
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.
Glucose levels can indicate diabetes, hypoglycemia, or other metabolic conditions. Chronic high levels may damage blood vessels over time, while low levels can cause dizziness or weakness. Regular monitoring helps prevent complications.
Short name
Glucose Level
Frequently asked questions
What causes my glucose levels to be high or low?
Do I need to prepare differently if I’m pregnant?
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