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Glucose in Serum (Mass Concentration)

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

This test measures the amount of glucose, a type of sugar, in your blood drawn from a vein. Glucose levels help assess how well your body is using food for energy.

Quick summary

["Checks your blood sugar levels to monitor energy metabolism and diabetes management."]

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

Key facts at a glance

LOINC
50217-9
Short code
Glucose sp8 SerPl-mCnc
Synonyms
Glucose sp8 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 Matters

Glucose is the primary energy source for your body’s cells. High or low levels can indicate health issues like diabetes, poor blood circulation, or other metabolic conditions. Your doctor may order this test to diagnose, monitor, or guide treatment for these conditions.

How the Test Works

A small sample of your blood is taken from a vein in your arm. The lab uses a specialized method to measure the glucose concentration in your serum (the liquid part of blood after clotting). This helps determine how much glucose is present at the time of testing.

What to Expect Before the Test

You may be asked to fast (not eat or drink except water) for a few hours before the test, depending on your doctor’s instructions. If you’re pregnant, have diabetes, or take certain medications, let your healthcare provider know. Avoid smoking or caffeine before the test to get the most accurate results.

What to Expect During the Test

The test is quick and painless. A healthcare professional will insert a small needle into your arm to draw blood. You may feel a slight pinch, but it usually takes only a few seconds. The blood sample is then sent to the lab for analysis.

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 Glucose

Frequently asked questions

How Often Should I Get This Test?
The frequency depends on your health status. People without diabetes may get this test occasionally as part of routine check-ups, while those with diabetes or prediabetes may need it more often—sometimes monthly or even weekly—to track blood sugar trends and adjust treatment as needed.
What Do My Results Mean?
Results are typically reported in milligrams per deciliter (mg/dL) or millimoles per liter (mmol/L). Your doctor will interpret these numbers in the context of your overall health and medical history. If your results are outside the expected range, further testing or follow-up may be recommended to understand the cause.
Can I Eat or Drink Before the Test?
If your doctor instructed a fasting test, avoid eating or drinking anything except water for a specified period before the test. If it’s a non-fasting test, you can eat and drink normally, but let your healthcare provider know if you’re unsure about your test instructions.
  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