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Insulin, mass concentration (serum/plasma)

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

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

Quick summary

["Insulin helps control how your body uses glucose (sugar) for energy."]

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

Key facts at a glance

LOINC
12765-4
Short code
Insulin 40M p chal SerPl-mCnc
Synonyms
Insulin 40M p chal SerPl-mCnc
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 Is Done

Your doctor may order this test to check for conditions like diabetes, hypoglycemia (low blood sugar), or other hormonal imbalances. It can also help monitor treatment for conditions affecting insulin production or function, such as pancreatitis or certain tumors.

What to Expect Before the Test

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

How the Test Is Done

A healthcare provider will draw blood from a vein in your arm using a small needle. You may feel a slight pinch, but it usually doesn’t cause much discomfort. The blood sample is sent to a lab for analysis.

What the Results Mean

Results are interpreted based on your medical history, symptoms, and other test results. High insulin levels might suggest insulinoma (a rare tumor) or other metabolic disorders, while very low levels could indicate diabetes or other endocrine 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

Could my insulin level be affected by what I eat or drink before the test?
Yes, fasting is often required for accurate results. If you have diabetes or take insulin, your doctor may adjust your routine or timing to avoid interference. Always follow your provider’s instructions.
Why might my doctor order this test if I have diabetes?
Your doctor may check insulin levels to confirm diabetes type (e.g., type 1 vs. type 2), assess insulin resistance, or evaluate complications like hypoglycemia. It can also help monitor treatment effectiveness.
Is there anything I should do to prepare for this test?
If fasting is required, avoid food or drink (except water) for 8–12 hours before testing. Wear comfortable clothing for the blood draw, and let your provider know about any medications or allergies.
  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