Glucose (Serum)
This test measures the amount of glucose, a type of sugar, in your blood serum. Glucose is the primary energy source for your body’s cells.
["Glucose levels help assess how well your body is using food for energy and managing blood sugar."]
Key facts at a glance
- LOINC
- 1543-8
- Short code
- Glucose 5M p .5 g/kg Glc IV SerPl-mCnc
- Synonyms
- Glucose 5M p .5 g/kg Glc IV 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 Is This Test Done?
Your healthcare provider may order this test to check for conditions like diabetes, high or low blood sugar, or to monitor treatment effectiveness. It can also help diagnose metabolic disorders or evaluate symptoms such as excessive thirst, fatigue, or unexplained weight changes.
What to Expect Before the Test
For this test, a small sample of blood is drawn from a vein, usually in your arm. You may feel a slight pinch when the needle is inserted, but it typically only takes a few minutes. Avoid eating or drinking anything (except water) for at least 8–12 hours before the test if instructed by your provider.
What to Expect During the Test
The blood sample is collected into a tube and sent to a lab for analysis. The test is quick and painless, though you might experience mild bruising or soreness at the injection site.
What the Results Mean
Results are usually reported in milligrams per deciliter (mg/dL). While reference ranges vary by lab, very high or very low levels may signal underlying health issues that need further evaluation. Your provider will interpret results in the context of your overall health 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.
Elevated glucose levels may indicate diabetes, insulin resistance, or other metabolic disorders. Persistently low levels can cause dizziness, confusion, or weakness. Regular monitoring is crucial for managing conditions like diabetes, where glucose control is essential for preventing long-term complications.
Short name
None
Frequently asked questions
What causes glucose levels to be different from what’s expected?
How often should I have this test?
Can lifestyle changes 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