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Insulin, Plasma (Concentration)

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

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

Quick summary

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

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

Key facts at a glance

LOINC
17018-3
Short code
Insulin 20M p chal SerPl-mCnc
Synonyms
Insulin 20M 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 Might Be Ordered

Your doctor may recommend this test to check for conditions like diabetes, insulin resistance, or other hormonal imbalances. It could also be used to monitor treatment for conditions affecting insulin production or function.

What to Expect Before the Test

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

During the Test

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

What the Results Mean

Results are interpreted by your doctor based on your medical history and symptoms. Abnormally high or low insulin levels can indicate underlying health issues, but exact values depend on the clinical context.

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

Plasma Insulin Level

Frequently asked questions

What Are Common Causes of Abnormal Results?
High insulin levels may suggest insulinoma (a rare tumor), Cushing’s syndrome, or other conditions affecting insulin metabolism. Low insulin levels could indicate diabetes, severe stress, or certain genetic disorders.
How Does This Test Relate to Blood Sugar?
Insulin works with blood sugar (glucose). High insulin often means your body is responding to high glucose levels, while low insulin may signal poor glucose regulation or insulin deficiency.
Can I Take My Medications Before the Test?
Yes, but always check with your doctor first. Some medications (like insulin or diabetes drugs) may affect results, so they may advise adjustments or timing.
  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