Skip to content

Glucose in Serum (Quantitative)

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.

Quick summary

["Your blood sugar levels help monitor conditions like diabetes or check for high or low sugar."]

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

Key facts at a glance

LOINC
41900-2
Short code
Glucose Mtr Dev Software vers
Synonyms
Glucose Mtr Dev Software vers
Category
chemistry
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
false
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

Doctors order this test to diagnose or monitor conditions such as diabetes, hypoglycemia (low blood sugar), or to check for signs of metabolic issues. It may also be used during pregnancy to screen for gestational diabetes or before certain surgeries to assess your body’s ability to handle stress.

What to Expect Before the Test

You may be asked to fast for 8–12 hours before the test if it’s part of a fasting blood sugar check. Otherwise, you can eat and drink normally. Bring any medications you’re taking, as some may affect results. Avoid smoking or chewing gum right before the test.

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 takes only a few seconds. The blood is then sent to a lab for analysis.

After the Test

You can return to your normal activities immediately. Apply gentle pressure to the site to stop any bleeding, and check the area for bruising or swelling. If you experience dizziness or lightheadedness, rest for a few minutes before resuming your day.

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 Level

Frequently asked questions

How often should I get this test if I have diabetes?
If you have diabetes, your doctor may recommend testing blood glucose levels at home daily or having lab tests every few months to track trends and adjust treatment plans. Follow your healthcare provider’s specific schedule.
Can food or medications affect my test results?
Yes, fasting before the test (if required) helps ensure accurate results. Certain medications (like insulin or some diabetes drugs) can lower blood sugar, while others (like steroids) may raise it. Always inform your doctor about all medications you’re taking.
What should I do if my blood sugar is very high or very low?
If you experience symptoms of extremely high blood sugar (e.g., frequent urination, extreme thirst, confusion) or very low blood sugar (e.g., shakiness, sweating, confusion), seek medical help immediately. For low blood sugar, consume fast-acting sugar (e.g., juice, candy) and contact a healthcare provider right away.
  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