Glucose, Serum or Plasma (Mass Concentration)
This test measures the amount of glucose (sugar) in your blood, typically drawn from a vein or collected in a tube.
["Glucose levels help assess blood sugar balance and identify risks for diabetes or other metabolic conditions."]
Key facts at a glance
- LOINC
- 2348-1
- Short code
- Glucose Snv-mCnc
- Synonyms
- Glucose Snv-mCnc
- Category
- glucose
- Sample
- fluid
- Container
- Sterile tube
- 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
- 2-5 mL
- Stability
- Room temperature: 2h, Refrigerated: 24h
- Hemolysis max
- 300
- TAT
- 4–24 hours
- Order
- routine
Why Is This Test Done?
Doctors order glucose tests to check for diabetes, monitor blood sugar control in people with diabetes, detect prediabetes, evaluate symptoms like extreme thirst or fatigue, or investigate unexplained weight changes or infections. It may also be used before surgeries or during pregnancy to ensure stable blood sugar levels.
What to Expect Before the Test
For blood tests, you may fast for 8–12 hours before the draw, though some labs allow a small sip of water. If you’re pregnant, have diabetes, or take certain medications, let your provider know. For plasma/serum tests, blood is collected in a tube without anticoagulants.
What Happens During the Test?
A healthcare provider will insert a small needle into your arm to draw blood. You may feel a brief pinch, but it’s over quickly. The sample is sent to a lab for measurement using an automated analyzer that detects glucose levels.
What to Expect After the Test
After the draw, you can resume normal activities. There may be a small bruise or redness at the site, but this usually fades within a day. If you experience excessive bleeding or pain, contact your provider.
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.
High glucose levels may indicate diabetes, poor insulin function, or stress-related spikes. Low levels could signal hypoglycemia, insulin overdose, or liver/kidney issues. Repeated tests help track trends over time and guide treatment decisions.
Short name
Glucose Level
Frequently asked questions
How long does it take to get results?
Can I eat or drink before this test?
Will I need to prepare for this test at home?
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