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Glucose, Serum or Plasma (Quantitative)

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
6752-0
Short code
Glucose 3.5h p 75 g Glc PO SerPl-mCnc
Synonyms
Glucose 3.5h p 75 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 This Test Matters

Glucose is the primary energy source for your body’s cells. Abnormal levels can indicate conditions like diabetes, hypoglycemia, or other metabolic disorders. Your healthcare provider may order this test to check for blood sugar imbalances, diagnose diabetes, or monitor treatment effectiveness.

How the Test Works

Blood is collected in a sterile tube and sent to a lab. The sample is analyzed using an automated method to measure glucose concentration in mass units per volume (e.g., mg/dL or mmol/L). The result reflects your recent blood sugar status.

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 checking fasting glucose levels. If you’re unsure, ask your provider for guidance.

What to Expect During the Test

A healthcare professional will insert a small needle into your arm to draw blood. You may feel a quick pinch, but it’s usually over quickly. The blood is then processed and sent to the lab for analysis.

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.

◆Associated findings1

Short name

None

Frequently asked questions

How often should I get this test?
Your provider will determine the frequency based on your health status. For example, people with diabetes may need tests every few months, while others may only need occasional checks.
What do my results mean?
Results are compared to a reference range provided by your lab. If your glucose is consistently high or low, your doctor may recommend lifestyle changes, medications, or further testing.
Can I eat or drink before this test?
If fasting is required, avoid food and liquids (except water) for the specified period. If not fasting, you can eat normally, but ask your provider to confirm.
  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