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Insulin, Serum (Quantitative)

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 or monitor diabetes and other metabolic conditions."]

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

Key facts at a glance

LOINC
56581-2
Short code
Insulin 12M p chal SerPl-aCnc
Synonyms
Insulin 12M p chal 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

Why This Test Might Be Ordered

Your doctor may recommend this test if you have symptoms of low blood sugar (hypoglycemia), such as shakiness, dizziness, or sweating, or if you have signs of high blood sugar (hyperglycemia), like frequent urination or excessive thirst. It may also be used to evaluate insulin resistance, pancreatic function, or to monitor treatment for diabetes or other endocrine disorders.

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 is part of a glucose tolerance or other metabolic study. If you are on insulin or diabetes medications, let your healthcare provider know.

How the Test Is Performed

A blood sample is drawn from a vein, typically in your arm, using a small needle. The sample is sent to a lab for analysis using an immunoassay method to detect insulin levels.

What the Results Mean

Results are not provided as a single numeric range since they depend on clinical context, such as fasting status or medical history. Your doctor will interpret the results in relation to your symptoms and other tests.

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

Serum Insulin Level

Frequently asked questions

What causes insulin levels to vary?
Insulin levels can fluctuate due to diet (especially carbohydrate intake), physical activity, stress, medications (including diabetes drugs), or underlying health conditions like diabetes, thyroid disorders, or liver disease. Fasting or recent meals can also temporarily affect results.
How long does it take to get results?
Results are typically available within 1–3 business days, depending on lab processing times. Your doctor will contact you once they are ready for review.
Can I eat or drink before this test?
If fasting is required (e.g., for a glucose study), avoid food and liquids except water for 8–12 hours beforehand. If no fasting is needed, you may eat normally, but check with your provider for specific instructions.
  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