Skip to content

Serum Glucose Concentration

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 assess how well your body is using glucose for energy and managing blood sugar levels.

Quick summary

["Check your blood sugar balance and identify potential diabetes or metabolic issues."]

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

Key facts at a glance

LOINC
77135-2
Short code
Glucose SerPlBld-sCnc
Synonyms
Glucose SerPlBld-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 It’s Done

Doctors order glucose tests to monitor conditions like diabetes, track blood sugar trends, or evaluate metabolic health. It may also be used during pregnancy, before surgeries, or to diagnose symptoms like excessive thirst, fatigue, or unexplained weight changes.

How It’s Done

A small needle is inserted into a vein in your arm. Blood is collected in a tube and sent to a lab for testing. The process usually takes a few minutes and may cause a brief sting or discomfort.

What to Expect Before the Test

No special preparation is needed for this test. However, if you’re fasting for another test, follow your healthcare provider’s instructions to avoid interfering with results. Wear comfortable clothing if you need to sit or lie down during the draw.

Possible Results and Interpretation

Results are typically reported in milligrams per deciliter (mg/dL) or millimoles per liter (mmol/L). While reference ranges vary by lab, lower or higher-than-normal levels may signal conditions like hypoglycemia (low blood sugar) or hyperglycemia (high blood sugar). Your doctor will discuss findings in the context of your health history.

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.

Clinical Significance

Short name

Glucose Level

Frequently asked questions

What does a high or low glucose level mean?
High glucose levels may indicate diabetes, insulin resistance, or other metabolic disorders. Repeatedly elevated levels can damage blood vessels and nerves over time. Low glucose levels (hypoglycemia) can cause dizziness, shakiness, or confusion and may require immediate medical attention.
How often should I get this test?
Your doctor will determine the frequency based on your health needs. For example, people with diabetes may need tests every few months, while others may only need occasional checks. Follow their guidance to avoid unnecessary testing or delays in care.
Can lifestyle changes affect this test?
Yes. Diet, exercise, hydration, and certain medications can influence blood sugar levels. If you’re making significant lifestyle changes, discuss them with your healthcare provider to ensure accurate results and avoid confusion with your treatment plan.
  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