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Glucose in Serum/Plasma (Mass Concentration)

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

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

Quick summary

["Your blood sugar levels help manage energy and metabolism."]

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

Key facts at a glance

LOINC
40005-1
Short code
Glucose 110m p chal SerPl-mCnc
Synonyms
Glucose 110m p chal 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 Is Done

Doctors may order this test to check for diabetes, monitor blood sugar levels in people with diabetes, or assess how your body handles glucose. It can also help diagnose conditions like hypoglycemia (low blood sugar) or evaluate metabolic health.

What to Expect Before the Test

You may be asked to fast (not eat) for several hours before the test, especially if it’s part of a glucose tolerance test. Otherwise, you can eat and drink normally unless instructed otherwise. Bring any medications you’re taking to your appointment.

During the Test

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 discomfort. The blood is then sent to a lab for analysis.

After the Test

You can usually return to your normal activities immediately. If you had a vein accessed for a longer procedure (like an IV), you may need to rest for a few minutes. Check with your provider if you experience any unusual bruising, swelling, or pain.

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

Serum/Plasma Glucose

Frequently asked questions

What does a high or low glucose result mean?
A high result may prompt further testing to confirm diabetes or check for other conditions like kidney disease or infections. A low result might require immediate medical attention, especially if you feel shaky, dizzy, or confused.
Can I eat or drink before this test?
If fasting is required (e.g., for a glucose tolerance test), follow your provider’s instructions. Otherwise, you can eat and drink normally unless specified otherwise.
How long will it take to get my results?
Results are typically available within 1–2 business days, depending on your lab and healthcare provider’s process. Follow-up instructions will be given if your results need further evaluation.
  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