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Glucose, Serum or Plasma (Mass Concentration)

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

This test measures the amount of glucose (sugar) in your blood drawn from either your vein or a fingerstick.

Quick summary

["Knowing your glucose levels helps manage blood sugar and prevent complications like diabetes-related issues."]

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

Key facts at a glance

LOINC
16169-5
Short code
Glucose 4 PM SerPl-mCnc
Synonyms
Glucose 4 PM 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?

Your healthcare provider may order this test to check for diabetes, monitor blood sugar levels, diagnose conditions like hypoglycemia, or assess how your body responds to treatments like insulin or medications.

What to Expect Before the Test

You may be asked to fast for 8–12 hours before the test if it’s part of a fasting glucose panel. Otherwise, you can eat and drink normally. Bring any medications you’re taking.

How the Test Is Performed

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

What the Results Mean

Results are compared to general reference ranges, but your specific target may vary based on your health goals, medications, or conditions. High or low readings may signal diabetes, prediabetes, or other metabolic issues.

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 outside normal ranges can indicate diabetes, hypoglycemia, or other metabolic disorders. Repeated testing may be needed to track trends over time, especially if you have a history of blood sugar fluctuations.

Short name

Glucose Level

Frequently asked questions

What causes my glucose levels to be tested?
Your doctor may test glucose levels if you have symptoms like excessive thirst, frequent urination, fatigue, or unexplained weight changes. It’s also part of routine check-ups for people at higher risk of diabetes.
How often should I get this test?
Frequency depends on your health status. People with diabetes typically get tests every 3–6 months, while others may need testing less often unless advised otherwise.
Can I eat or drink before the test?
If fasting is required, avoid food for 8–12 hours before testing. If not fasting, you can eat and drink normally, but check with 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