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Glucose, Serum

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

This test measures the amount of glucose (sugar) in your blood drawn from a vein in your arm. It helps doctors check how well your body is using sugar for energy.

Quick summary

A glucose test helps monitor blood sugar levels, often used in diabetes management or general health checks.

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

Key facts at a glance

LOINC
1498-5
Short code
Glucose 10M p .5 g/kg Glc IV SerPl-mCnc
Synonyms
Glucose 10M p .5 g/kg Glc IV 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 doctor may order this test to diagnose or monitor conditions like diabetes, high blood sugar, or to assess how your body processes sugar. It can also be part of routine check-ups or before certain treatments.

What to Expect Before the Test

No special preparation is 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 blood sugar check. Bring any medications you’re taking with you.

What Happens During the Test?

A healthcare provider will insert a small needle into 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.

What Do the Results Mean?

Results are typically reported in milligrams per deciliter (mg/dL). High or low levels can signal health concerns, so discuss your results with your doctor.

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.

This test is critical for diagnosing diabetes, assessing metabolic health, and guiding treatment plans. Abnormal results may indicate conditions like hypoglycemia (low blood sugar) or hyperglycemia (high blood sugar), which require medical attention.

Short name

Glucose Level

Frequently asked questions

What causes abnormal glucose levels?
Factors like diet, exercise, stress, illness, or certain medications can affect blood sugar. Chronic conditions like diabetes or kidney disease may also influence results.
How often should I get this test?
Your doctor will determine how often you need this test based on your health status. For example, people with diabetes may need tests more frequently than others.
Can I eat or drink before the test?
If fasting is required, avoid food and liquids (except water) for the specified time. Follow your doctor’s instructions to ensure accurate results.
  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