Glucose, Plasma or Serum (Mass Concentration)
This test measures the amount of glucose (sugar) in your blood plasma or serum. It helps assess how well your body is using sugar for energy and managing blood sugar levels.
["A glucose test helps check for diabetes, blood sugar control, or metabolic issues."]
Key facts at a glance
- LOINC
- 16168-7
- Short code
- Glucose 3 PM SerPl-mCnc
- Synonyms
- Glucose 3 PM SerPl-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 It’s Done
Doctors order a glucose test to diagnose conditions like diabetes, monitor blood sugar levels over time, or evaluate how your body processes sugar. It may also be used before surgeries, during pregnancy, or if you have symptoms like excessive thirst, frequent urination, or unexplained weight changes.
What to Expect
A blood sample is taken from a vein in your arm, usually while you’re lying down. The sample is sent to a lab for analysis. Plasma or serum (liquid part of blood without or with clotted blood) is used, depending on the test method. Results may be reported as a concentration in milligrams per deciliter (mg/dL) or other units.
How It Works
The test detects glucose molecules in your blood using methods like enzymatic reactions or immunoassays. These methods measure how much sugar is present without affecting other blood components.
Normal vs. Abnormal Results
While reference ranges vary by lab, consistently high or low glucose levels may signal diabetes, hypoglycemia, or other metabolic disorders. Your doctor will interpret results in the context of your symptoms and medical history.
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), assessing prediabetes, and monitoring long-term complications like nerve damage or kidney issues. Frequent testing may also help prevent complications in people with known diabetes or prediabetes.
Short name
Glucose Level
Frequently asked questions
What does a glucose test measure?
How often should I get a glucose test?
Can fasting affect my 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