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Serum Insulin Concentration (Quantitative)

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

This test measures the amount of insulin, a hormone produced by your pancreas, in your blood. Insulin helps regulate blood sugar levels.

Quick summary

["Insulin levels help diagnose and monitor diabetes and other metabolic conditions."]

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

Key facts at a glance

LOINC
66156-1
Short code
Diabetes insulin PhenX
Synonyms
Diabetes insulin PhenX
Category
hormone
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
2.6
Ref high
24.9
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
phenx
CPT
83525
SNOMED
413618004
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 doctor may order this test to check for diabetes, insulin resistance, or other hormonal imbalances. It can also help evaluate symptoms like unexplained weight changes, fatigue, or unusual thirst/urination.

When Might You Need This Test?

You might need this test if you have symptoms of low or high blood sugar, if you’re being evaluated for diabetes, or if your doctor suspects a condition affecting insulin production.

What Does the Test Involve?

A blood sample is taken from a vein in your arm. The sample is sent to a lab where insulin levels are measured using an immunoassay method.

What Do Results Mean?

Results provide a quantitative measure of insulin in your blood, but interpretation depends on clinical context (e.g., fasting vs. non-fasting status) and other tests like glucose levels.

Reference range

Fasting: 2.6-24.9 μIU/mLN/A

Specimen: serum

No special preparation usually required. Stay well hydrated. Inform your healthcare provider of all medications and supplements you are taking.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Insulin Level

Frequently asked questions

What causes abnormal insulin levels?
Abnormally high insulin levels may occur with insulin-producing tumors, certain cancers, or severe pancreatitis. Low levels can result from diabetes, pancreatic disease, or medications that suppress insulin secretion.
How long does it take to get results?
Results are typically available within 1–3 business days, depending on lab processing times and your healthcare provider’s workflow.
Can I eat or drink before this test?
If fasting is required (check with your doctor), avoid food and liquids except water for 8–12 hours before testing. If not fasting, eat a normal meal, but confirm instructions with your 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