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Insulin, Serum/Plasma — Substance Concentration

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

Measures insulin levels in blood to help evaluate blood sugar control, insulin resistance, and the function of pancreatic beta cells.

Quick summary

["This blood test shows how much insulin your body is producing or releasing at the time of testing."]

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

Key facts at a glance

LOINC
56482-3
Short code
Insulin BS SerPl-aCnc
Synonyms
Insulin BS 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 in serum or plasma. Insulin is a hormone made by the pancreas that helps glucose enter cells for energy.

Why might I need this test?

A clinician may order this test when evaluating diabetes, unusually low blood sugar, or possible insulin resistance. It may also be used alongside glucose and other tests to assess treatment or determine how the body responds to a glucose challenge.

How is the test performed?

A blood sample is drawn from a vein, usually from the arm. The sample is analyzed in a laboratory using an immunoassay or a similar validated method to determine the insulin concentration.

How do I prepare for the test?

Follow your clinician's instructions about fasting and medication timing, because food intake and insulin medicines can affect the result. If the test is part of a glucose tolerance test, the timing of the blood draw is especially important.

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 Test

Frequently asked questions

Does this test diagnose diabetes?
No. An insulin result is interpreted with glucose and other clinical information, so it is not a stand-alone diagnostic test for diabetes.
Why might I need both insulin and glucose testing?
The two results are more informative together because they show how insulin relates to blood sugar at the same time.
Can insulin medicines affect the result?
Yes. Insulin injections and some diabetes medicines can change insulin levels, so tell your clinician about the medicines and doses you use.
  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