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Glucose, Serum (Mass Concentration)

Published: August 9, 2026Updated: August 16, 2026

This test measures the amount of glucose (sugar) in your blood drawn from a vein in your arm. It helps assess how well your body is using sugar for energy and managing blood sugar levels.

Quick summary

["A glucose test helps check for diabetes, high or low blood sugar, or other metabolic conditions."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
2342-4
Short code
Glucose CSF-mCnc
Synonyms
Glucose CSF-mCnc
Category
glucose
Sample
csf
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
1-2 mL
Stability
Immediate analysis required, Refrigerated: 1h
Hemolysis max
200
TAT
4–24 hours
Order
routine

Why This Test Might Be Ordered

Your healthcare provider may recommend this test if you have symptoms like excessive thirst, frequent urination, unexplained weight changes, fatigue, or recurring infections. It’s also used to monitor blood sugar levels in people with diabetes or those at risk of developing diabetes.

What to Expect Before the Test

No special preparation is needed unless instructed. You may be asked to fast (not eat or drink anything except water) for 8–12 hours before the test if it’s part of a fasting glucose check. Otherwise, you can eat and drink normally.

How the Test Is Performed

A healthcare provider will insert a small needle into your arm to draw blood. You may feel a slight pinch, but the procedure usually takes a few minutes. The blood sample is sent to a lab for analysis.

What the Results Mean

Results are compared to standard reference ranges, but your specific values will be interpreted by your healthcare provider based on your medical history and symptoms. Abnormal results may indicate conditions like diabetes, hypoglycemia, or other metabolic disorders.

Reference range

Fasting: 70-100 mg/dLN/A

Specimen: csf

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.

◆Associated findings1

Short name

Glucose Level

Frequently asked questions

What Are Common Causes of Abnormal Results?
High glucose levels may be caused by diabetes, stress, illness, or certain medications. Low glucose levels (hypoglycemia) can result from excessive insulin, certain foods, or medical conditions like liver disease.
How Often Should I Get This Test?
Your provider will determine the frequency based on your health needs. Regular testing may be recommended if you have diabetes, prediabetes, or other conditions affecting blood sugar.
Can I Eat or Drink Anything Before the Test?
If fasting is required, avoid food and liquids (except water) for 8–12 hours beforehand. If not fasting, eat and drink normally, but check with your provider for any specific instructions.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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