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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, a type of sugar, in your blood. Glucose is your body’s main source of energy.

Quick summary

["Checks how well your body uses sugar for energy and helps monitor conditions like diabetes."]

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

Key facts at a glance

LOINC
25676-8
Short code
Glucose 5.5h p Glc SerPl-sCnc
Synonyms
Glucose 5.5h p Glc SerPl-sCnc
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

Your healthcare provider may order this test to check for diabetes, high or low blood sugar, or to monitor existing conditions like prediabetes, hypoglycemia, or metabolic disorders. It can also help assess how well medications are working or if you’re at risk for complications like nerve damage or kidney issues.

How the Test Works

A small sample of your blood (either serum or plasma) is collected and analyzed using high-performance liquid chromatography (HPLC). This method separates and measures glucose with high accuracy.

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 glucose study. If you’re not fasting, drinking water is fine.

What to Expect During the Test

A healthcare professional will draw blood from a vein in your arm. You may feel a slight pinch, but it usually doesn’t cause discomfort. The test itself takes only a few minutes.

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

Glucose Level

Frequently asked questions

What does a high or low glucose result mean?
A high glucose result may mean you have diabetes or prediabetes, or that your body isn’t using insulin properly. A low result could signal hypoglycemia, especially if you’re taking diabetes medications or insulin. Your doctor will discuss your results with you and may recommend lifestyle changes, medication adjustments, or further testing.
How often should I get this test?
Your doctor will determine how often you need this test based on your health condition. For people with diabetes, tests may be done more frequently (e.g., every 3–6 months) to track blood sugar trends. Others may need it less often, depending on risk factors or symptoms.
Can I eat or drink anything before the test?
If your test is part of a fasting study, avoid food and liquids (except water) for 8–12 hours beforehand. If it’s a non-fasting test, you can eat and drink normally, but let your doctor know if you’re unsure.
  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