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Glucose in Plasma or Serum (Quantitative)

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

This test measures the amount of glucose (sugar) in your blood plasma or serum. It helps monitor blood sugar levels, often used in diabetes management or to check for conditions like hypoglycemia or hyperglycemia.

Quick summary

["Blood sugar levels are critical for energy and overall health—this test helps track them."]

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

Key facts at a glance

LOINC
41897-0
Short code
Glucose Mtr Dev Vendor name
Synonyms
Glucose Mtr Dev Vendor name
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 Is This Test Done?

Your healthcare provider may order this test to diagnose or manage diabetes, assess blood sugar control, detect signs of low blood sugar (hypoglycemia), or evaluate metabolic health. It may also be used in emergency settings to check for conditions like severe dehydration or shock.

How Is the Test Performed?

A small blood sample is taken from a vein in your arm. The sample is sent to a lab where glucose levels are measured using an automated method, such as enzymatic analysis, to determine your current blood sugar concentration.

What Do Results Mean?

Results provide a snapshot of your glucose concentration at the time of testing. While reference ranges vary by lab, higher or lower-than-expected levels may signal diabetes, prediabetes, or other metabolic issues that require further evaluation.

Common Reasons for Abnormal Results

Elevated glucose levels may indicate diabetes, poor insulin function, or recent high-carb intake. Low levels can signal hypoglycemia, excessive insulin or medication use, or certain medical conditions. Always discuss results with your provider.

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

How often will I need this test?
Frequency depends on your health condition. People with diabetes typically test every few months or more often if managing blood sugar closely. Others may need it less frequently, such as during routine check-ups or before certain treatments.
What should I do if my glucose level is too high or too low?
If your results are outside expected ranges, follow your healthcare provider’s instructions. For high levels, lifestyle changes (diet, exercise) or medication adjustments may be needed. For low levels, eat a quick source of sugar (e.g., fruit juice) and seek medical help if symptoms like dizziness or confusion occur.
Can I eat or drink before the test?
Most glucose tests require fasting (no food or drink except water) for 8–12 hours before collection. Non-fasting tests may be done for urgent or specific clinical reasons—always confirm with your lab or provider.
  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