Glucose, Serum or Plasma (Concentration)
This test measures the amount of glucose, a type of sugar, in your blood serum or plasma. It helps assess how your body uses energy and manages blood sugar levels.
["A glucose test helps monitor blood sugar control, especially important for diabetes management."]
Key facts at a glance
- LOINC
- 40205-7
- Short code
- Glucose 14m p chal SerPl-sCnc
- Synonyms
- Glucose 14m p chal 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 This Test Is Done
Your healthcare provider may order this test to check for diabetes or prediabetes, evaluate symptoms like excessive thirst or fatigue, or monitor long-term blood sugar control in people with known diabetes. It can also be used to diagnose conditions affecting metabolism or to assess response to treatments.
What to Expect Before the Test
No special preparation is needed for this test. If it’s a fasting test, you’ll typically fast for 8–12 hours before drawing blood. Otherwise, you may eat and drink normally. Avoid smoking or caffeine for 30 minutes before the test if instructed.
What Happens During the Test
A healthcare professional will insert a small needle into your arm to draw blood. You may feel a slight pinch, but it usually doesn’t cause discomfort. The blood sample is then sent to a lab for analysis using an enzymatic method to measure glucose concentration.
What the Results Mean
Results are compared to general reference ranges, though individual ranges may vary by lab. High or low glucose levels can signal diabetes, metabolic disorders, or other health issues. Your provider will interpret results in the context of your overall health and symptoms.
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 (both type 1 and type 2), identifying prediabetes, and monitoring chronic conditions. Persistently high or low levels can indicate underlying health risks, including nerve damage, kidney problems, or cardiovascular disease. Regular monitoring helps prevent complications and guides treatment decisions.
Short name
Glucose Level
Frequently asked questions
What causes glucose levels to be tested?
How long does it take to get results?
Can lifestyle changes affect glucose test 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