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Insulin, Serum/Plasma — Concentration

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

A blood test that measures the amount of insulin in serum or plasma to help evaluate how the body regulates blood glucose.

Quick summary

["This test measures insulin in the blood and is usually interpreted together with blood glucose and the clinical situation."]

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

Key facts at a glance

LOINC
93793-8
Short code
Insulin Mean SerPl-aCnc
Synonyms
Insulin Mean SerPl-aCnc
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

What is this test?

This test measures the concentration of insulin, a hormone made by the pancreas that helps cells take up glucose for energy. The result may be evaluated alone or alongside a glucose test.

Why might I need this test?

A clinician may order this test when evaluating symptoms of high or low blood glucose, insulin resistance, diabetes, or conditions that affect pancreatic function. It may also be used to monitor certain treatments.

How is the test performed?

A blood sample is collected by venipuncture and analyzed by a laboratory. The laboratory measures the amount of insulin present in the serum or plasma portion of the sample.

How do I prepare for the test?

Follow your clinician's instructions about fasting and medication timing. Fasting for several hours may be requested, especially when insulin is being interpreted with glucose, but requirements can vary by reason for testing.

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 Blood Test

Frequently asked questions

Do I need to fast before this test?
Sometimes. Your clinician may request a fasting test, particularly when the insulin result will be compared with a glucose measurement. Follow the specific instructions provided for your order.
Is a high insulin level always a sign of diabetes?
No. Insulin can be elevated for several reasons, including insulin resistance, recent food intake, and certain medications. Glucose levels, symptoms, medications, and other test results must be considered together.
Can insulin injections affect the test result?
Yes. Exogenous insulin may influence the measured level, so tell your clinician about insulin injections and the timing of your most recent dose.
  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