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Glucose in Serum or Plasma (Mass Concentration)

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

This test measures the amount of glucose, a simple sugar, present in your blood. Glucose is your body’s primary energy source and is closely regulated to maintain healthy levels.

Quick summary

["Essential for monitoring blood sugar and managing conditions like diabetes."]

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

Key facts at a glance

LOINC
27328-4
Short code
GH sp6 p chal SerPl-mCnc
Synonyms
GH sp6 p chal SerPl-mCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 high or low blood sugar levels, diagnose conditions like diabetes, or monitor treatment effectiveness. It’s often used in routine check-ups, emergency situations, or before certain procedures.

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 panel. Bring any medications you’re taking to your appointment.

What Happens During the Test?

A healthcare professional will draw blood from a vein in your arm using a small needle. You may feel a slight pinch, but it’s usually over quickly. The blood sample is then sent to a lab for analysis.

What Do Results Mean?

Results help determine if your blood sugar is within a healthy range or if further action is needed. Abnormally high or low levels may signal diabetes, hypoglycemia, or other metabolic issues.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Serum/Plasma Glucose

Frequently asked questions

Why might my doctor want to check my glucose levels regularly?
If you have diabetes or are at risk for it, frequent glucose checks help track how well your body is managing blood sugar. This helps prevent complications like nerve damage, kidney issues, or heart disease.
What if my glucose levels are too high or too low?
High levels may require lifestyle changes, medication adjustments, or monitoring for diabetes. Low levels (hypoglycemia) can cause dizziness, shakiness, or confusion and may need immediate treatment like glucose or snacks.
Can I eat or drink anything before this test?
For fasting tests, avoid food and liquids (except water) for 8–12 hours before drawing blood. If your test isn’t fasting-related, follow any specific instructions your provider gives you.
  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