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Glucose, Serum/Plasma, Mass Concentration

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

This test measures the amount of glucose (sugar) in your blood, typically drawn from a vein or collected in a tube.

Quick summary

["Glucose levels help monitor blood sugar and identify potential diabetes or metabolic issues."]

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

Key facts at a glance

LOINC
1544-6
Short code
Glucose 6h p 100 g Glc PO SerPl-mCnc
Synonyms
Glucose 6h p 100 g Glc PO 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?

Doctors order glucose tests to check for conditions like diabetes, high or low blood sugar, or to monitor treatment effectiveness. It may also be part of routine check-ups or before certain procedures.

What to Expect Before the Test

You may be asked to fast (not eat or drink) for 8–12 hours before the test, depending on the reason. If fasting isn’t required, you can eat and drink normally. Bring any medications you’re taking.

How the Test Is Performed

A healthcare provider will insert a small needle into a vein in your arm to draw blood. You may feel a slight pinch, but it usually doesn’t cause pain. The blood is sent to a lab for analysis.

What the Results Mean

Results are compared to standard ranges, but exact values can vary by lab. High or low readings may signal diabetes, hypoglycemia, or other health concerns that need further evaluation.

Reference range

Fasting: 70-100 mg/dLN/A

Specimen: serum

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 energy production and nerve function. Chronic high or low levels can damage organs, increase infection risk, or worsen existing conditions like heart disease or kidney problems.

Short name

Glucose Level

Frequently asked questions

How long does it take to get my glucose test results?
Results are typically available within 1–3 business days, depending on your lab. Follow-up with your doctor if you have questions about your results.
Can I eat or drink before this test?
If fasting is required, avoid food and liquids (except water) for 8–12 hours before testing. Check with your provider for specifics based on your reason for the test.
What should I do if I have very low or very high blood sugar?
If you experience symptoms like dizziness, confusion, or excessive thirst, seek medical attention immediately. For high blood sugar, drink water and check with your doctor about adjusting medications if needed.
  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