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Glucose in Serum (Glucose Level)

Published: August 9, 2026Updated: August 17, 2026

This test measures the amount of glucose, a type of sugar, in your blood serum. Glucose is the primary energy source for your body’s cells.

Quick summary

["Your blood sugar levels help determine how your body uses energy and manage conditions like diabetes."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
32546-4
Short code
G6PD RBC-cCnt
Synonyms
G6PD RBC-cCnt
Category
glucose
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Ref low
4.2
Ref high
5.9
Critical range
2 N/A – 7 N/A
Fasting
true
Population
adult
Sex
all
Age range
18–65 years
CPT
85041
SNOMED
900000000000003001
Specimen volume
3 mL
Stability
Room temperature: 4h, Refrigerated: 24h
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

Why Is This Test Done?

Doctors may order a serum glucose test to check for diabetes, monitor blood sugar levels in people with diabetes, diagnose conditions like hypoglycemia (low blood sugar), or evaluate symptoms such as excessive thirst, frequent urination, or unexplained weight changes.

What to Expect During the Test

A healthcare provider will draw blood from a vein in your arm. You may feel a slight pinch or discomfort, but it usually lasts only a few seconds. The blood sample is then sent to a lab for analysis.

How Results Are Interpreted

Results are typically reported in milligrams per deciliter (mg/dL) or millimoles per liter (mmol/L). Your doctor will compare these results to your specific reference range and medical history to determine if further action is needed.

Common Conditions Monitored

This test is often used to diagnose or manage diabetes, prediabetes, hypoglycemia, and other metabolic disorders. It can also help assess how well treatments like medication or insulin are working.

Reference range

Adult males: 4.2-5.9; Females: 3.8-5.1 x 10^12/LN/A

Specimen: whole-blood

No special preparation required. Stay well hydrated.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Serum glucose levels can provide critical insights into your metabolic health. High levels may indicate diabetes or insulin resistance, while low levels can signal hypoglycemia or other endocrine issues. Regular monitoring is essential for people with chronic conditions like diabetes.

Short name

Serum Glucose

Frequently asked questions

What causes abnormal serum glucose levels?
Abnormal serum glucose levels can result from lifestyle factors (e.g., diet, physical activity), underlying medical conditions (e.g., diabetes, pancreatitis), medications (e.g., steroids, insulin), or stress. If you notice frequent fluctuations, discuss these with your doctor.
How often should I get this test?
Frequency depends on your health status. People without diabetes may get tested occasionally for screening, while those with diabetes typically check levels more regularly (e.g., every 3–6 months) as advised by their healthcare provider.
Can diet or exercise affect test results?
Yes, diet and exercise can influence blood sugar levels. If you’re fasting for the test, avoid eating or drinking anything except water for the specified period. If you’re active, note any recent physical activity, as it may temporarily affect 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 17, 2026. · Read our editorial policy