Glucose, Plasma or Serum
This test measures the amount of glucose (sugar) in your blood plasma or serum, which helps assess your blood sugar levels.
["Glucose levels indicate how your body uses energy and can signal diabetes or other metabolic conditions."]
Key facts at a glance
- LOINC
- 2347-3
- Short code
- Glucose Prt-mCnc
- Synonyms
- Glucose Prt-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 Is This Test Done?
Your healthcare provider may order this test to check for high or low blood sugar, monitor diabetes management, diagnose conditions like hypoglycemia or hyperglycemia, or evaluate metabolic health. It’s often part of routine check-ups or when symptoms like fatigue, frequent urination, or blurred vision appear.
What to Expect Before the Test
For blood tests, you’ll typically have a small needle inserted into your arm to draw blood. If fasting is required (common for glucose tests), avoid eating or drinking (except water) for 8–12 hours beforehand. If fasting isn’t needed, you can eat normally, but hydration is still important. Wear comfortable clothing and bring any medications you’re currently taking.
What Happens During the Test?
The blood sample is collected in a tube and sent to a lab, where it’s analyzed to measure glucose concentration. Results are usually ready within a few hours to a day, depending on your lab’s processing time. You’ll receive your results from your healthcare provider.
What the Results Mean
Results are compared to standard ranges, but exact values can vary by lab. High glucose levels may indicate diabetes or poor blood sugar control, while very low levels could signal hypoglycemia or other issues. Your provider will interpret results in the context of your symptoms, medical history, and other tests.
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 are critical for diagnosing diabetes, monitoring treatment effectiveness, and detecting metabolic disorders. Chronic high glucose can damage blood vessels and nerves, increasing risks for heart disease, kidney problems, or nerve damage. Regular monitoring helps prevent complications and guides lifestyle or medication adjustments.
Short name
None
Frequently asked questions
How often should I get this test?
What do my results mean if they’re outside the normal range?
Can I eat or drink 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