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Insulin, Serum

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

This test measures the amount of insulin, a hormone produced by the pancreas, in your blood serum. It helps assess how well your body regulates blood sugar.

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
5232-4
Short code
Insulin Ab Ser RIA-aCnc
Synonyms
Insulin Ab Ser RIA-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
Method
ria
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 Is This Test Done?

Your healthcare provider may order this test to check for diabetes or prediabetes, evaluate symptoms like unexplained weight changes or fatigue, or monitor treatment for conditions affecting blood sugar. It can also help diagnose insulin resistance or other hormonal imbalances.

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 study. Bring any medications you’re taking, as some may affect results.

How the Test Is Performed

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

What the Results Mean

Results are interpreted based on your overall health, symptoms, and other test results. High insulin levels may indicate insulin resistance or other metabolic issues, while very low levels could suggest hormonal disorders or pancreatic problems.

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.

Clinical Significance: Insulin Levels Play a Key Role in Blood Sugar Regulation and Metabolic Health. Abnormal results may signal diabetes, insulin resistance, or conditions like hypoglycemia, which require further evaluation by your healthcare provider.

Short name

Serum Insulin

Frequently asked questions

What causes insulin levels to be unusually high?
High insulin levels can result from diabetes (especially type 2), insulin resistance, certain medications, or conditions like acromegaly. Lifestyle factors, such as obesity or poor diet, may also contribute.
What happens if my insulin levels are low?
Low insulin levels may indicate diabetes, pancreatic issues, or hormonal imbalances. Symptoms like dizziness, shakiness, or unexplained weight loss could signal hypoglycemia or other metabolic problems.
Do insulin tests always require fasting?
Not always. Some tests are done without fasting, while others (like glucose tolerance tests) require fasting or specific timing around meals. Your provider will guide you on preparation.
  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