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Insulin, Serum Concentration (Quantitative)

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

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

Quick summary

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

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

Key facts at a glance

LOINC
55382-6
Short code
Insulin 5M p chal SerPl-sCnc
Synonyms
Insulin 5M p chal SerPl-sCnc
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
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 This Test Might Be Ordered

Your healthcare provider may order this test to check for diabetes, insulin resistance, or other hormonal imbalances. It could also be used to evaluate symptoms like unexplained weight changes, fatigue, or frequent urination.

What to Expect Before the Test

No special preparation is needed, but you may be asked to fast for 8–12 hours before the test if it’s part of a glucose-insulin profile. Bring any medications you’re currently taking to your appointment.

How the Test Works

A blood sample is drawn from a vein, usually in your arm. The sample is sent to a lab where it’s analyzed using an immunoassay method to measure insulin concentration.

What the Results Mean

Results are typically reported in micrograms per deciliter (µg/dL) or nanograms per milliliter (ng/mL). Higher-than-normal levels may indicate insulinoma or other conditions, while very low levels could suggest diabetes or pancreatic issues.

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

How long does it take to get results?
Results are usually available within 1–3 business days, depending on your lab’s processing time. Your healthcare provider will contact you once they’re ready to review them.
What causes insulin levels to be too high?
High insulin levels may be caused by insulin-producing tumors (insulinoma), certain medications, or conditions like reactive hypoglycemia. Lifestyle factors, such as diet or stress, can also temporarily affect levels.
Can diet affect insulin test results?
Yes, fasting before the test is important to avoid misleading results. If you have questions about timing, ask your provider or lab technician.
  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