Glucose, Serum or Plasma (Mass Concentration)
This test measures the amount of glucose (sugar) in your blood, drawn from either serum or plasma. It helps assess how well your body is managing blood sugar levels.
["A glucose test helps diagnose or monitor conditions like diabetes or check for high blood sugar."]
Key facts at a glance
- LOINC
- 48988-0
- Short code
- Glucose 12 PM SerPl-mCnc
- Synonyms
- Glucose 12 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 Is This Test Done?
Your healthcare provider may order this test to check for diabetes, monitor blood sugar levels during treatment, or evaluate symptoms like excessive thirst, frequent urination, or unexplained weight changes. It can also be used to screen for conditions affecting metabolism or to assess how well medications are working.
What to Expect Before the Test
No special preparation is usually needed, but you may be asked to fast (not eat or drink) for 8–12 hours before the test if it’s part of a fasting blood sugar check. If you’re not fasting, you can eat and drink normally. Bring any medications you’re currently taking to your appointment.
What Happens During the Test?
A healthcare professional will insert a small needle into a vein in your arm or hand to draw blood. You may feel a slight pinch or sting, but it usually doesn’t cause significant discomfort. The blood sample will be sent to a lab for analysis.
What to Expect After the Test
After the blood is drawn, the needle site will be covered with a bandage. You can resume normal activities immediately. If you experience bruising, swelling, or excessive bleeding, 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, prediabetes, or other metabolic disorders. Consistently low levels could signal hypoglycemia (low blood sugar), which can cause dizziness, shakiness, or confusion. Regular monitoring helps prevent complications like nerve damage, kidney issues, or heart disease.
Short name
Glucose Level
Frequently asked questions
What Does a Glucose Test Tell Me?
How Often Should I Get This Test?
Can I Eat or Drink Before the 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