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Glucose, Plasma or Serum (Mass Concentration)

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

This test measures the amount of glucose (sugar) in your blood plasma or serum, a key indicator of your blood sugar levels.

Quick summary

["Glucose levels help monitor diabetes and other metabolic conditions."]

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

Key facts at a glance

LOINC
6300-8
Short code
Glucose Amn-mCnc
Synonyms
Glucose Amn-mCnc
Category
glucose
Sample
fluid
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
2-5 mL
Stability
Room temperature: 2h, Refrigerated: 24h
Hemolysis max
300
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 control, diagnose hypoglycemia (low blood sugar), or assess how your body processes glucose. It’s often used in routine check-ups, emergency situations, or before certain treatments.

How Is the Sample Collected?

A small amount of blood is drawn from a vein in your arm by a healthcare professional. The blood is then separated into plasma or serum for testing.

What Do Results Mean?

Results are typically reported in milligrams per deciliter (mg/dL) or millimoles per liter (mmol/L). While reference ranges vary by lab, very high or very low values may signal underlying health concerns.

Common Causes of Abnormal Results

Elevated glucose levels may indicate diabetes, poor insulin function, or stress-related spikes. Low levels can result from insulin overdose, severe illness, or certain medications.

Reference range

Fasting: 70-100 mg/dLN/A

Specimen: fluid

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.

This test is critical for diagnosing diabetes (including type 1 and type 2), assessing prediabetes, managing blood sugar in patients with chronic conditions, and detecting hypoglycemia. It also helps evaluate metabolic disorders or monitor treatment effectiveness.

Short name

Plasma/Serum Glucose

Frequently asked questions

What if I Have Diabetes and My Glucose Is High?
If your glucose is consistently high, follow your doctor’s advice for lifestyle changes (diet, exercise) or medication adjustments. Regular monitoring helps keep levels stable.
Can I Fast Before This Test?
Yes, fasting (not eating or drinking except water) for 8–12 hours before the test is often required to get an accurate reading, especially if checking for diabetes.
How Long Does It Take to Get Results?
Results are typically available within 1–2 business days, depending on your lab’s processing time. Your provider will discuss them with you during your follow-up.
  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