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Glucose, Serum or Plasma (High-Performance Liquid Chromatography)

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

This test measures the amount of glucose (sugar) in your blood, typically drawn from a vein or capillary site.

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
9377-3
Short code
Glucose 4.5h p 100 g Glc PO SerPl-mCnc
Synonyms
Glucose 4.5h p 100 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 Is This Test Done?

Your healthcare provider may order this test to check for diabetes, monitor blood sugar control, diagnose conditions like hypoglycemia, or assess how your body processes glucose. It’s also used in routine check-ups or during pregnancy to track health.

What to Expect Before the Test

You may be asked to fast for 8–12 hours before the test, especially if it’s a fasting glucose check. Otherwise, you can eat and drink normally. Avoid smoking or caffeine for 30 minutes before the draw.

During the Test

A healthcare professional will insert a small needle into your arm or finger to collect a blood sample. You may feel a slight pinch, but it’s usually over quickly. If drawn from a vein, you might experience mild discomfort.

After the Test

You can resume normal activities immediately. Apply gentle pressure to the site to stop bleeding, and avoid rubbing it. If you experience excessive bruising or pain, contact your provider.

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.

High glucose levels may indicate diabetes, prediabetes, or other metabolic disorders, while low levels could signal hypoglycemia or other health risks. Regular monitoring helps prevent complications like nerve damage, kidney issues, or heart disease.

Short name

Glucose Level

Frequently asked questions

What does a high or low glucose result mean?
A high result may mean your body isn’t using insulin properly or isn’t producing enough, which could signal diabetes or insulin resistance. A low result may indicate your body is using insulin too quickly or could be caused by certain medications.
How often should I get this test?
Your provider will determine how often you need this test based on your health status, symptoms, and treatment plan. For example, people with diabetes may check it more frequently than others.
Can I eat or drink before this test?
If fasting is required, follow your provider’s instructions. If not, you can eat and drink normally, but avoid caffeine or smoking before the draw.
  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