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Insulin, Serum (Quantitative)

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

This test measures the amount of insulin present in your blood serum, which helps assess how your body produces and uses insulin for regulating blood sugar levels.

Quick summary

["Insulin levels help diagnose or monitor conditions like diabetes or insulin resistance."]

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

Key facts at a glance

LOINC
57007-7
Short code
Insulin 52h p chal SerPl-aCnc
Synonyms
Insulin 52h 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 Is This Test Done?

Your healthcare provider may order this test to check for diabetes, insulin resistance, or other metabolic disorders. It can also help evaluate symptoms like unexplained weight changes, fatigue, or frequent urination that may relate to blood sugar imbalances.

What to Expect Before the Test

No special preparation is needed, but you may be asked to fast for 8–12 hours before the test if it’s part of a glucose tolerance or other metabolic study. Bring any medications you’re currently taking.

How the Test Works

A blood sample is drawn from a vein, usually in your arm. The serum portion is then analyzed using an immunoassay method to measure insulin concentration.

Possible Results and Interpretation

Results are compared to general reference ranges, though individual labs may vary. High levels may indicate insulinoma or other endocrine issues, while low levels could suggest diabetes or inadequate insulin production.

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.

Abnormal insulin levels can signal diabetes, hypoglycemia, or conditions like Cushing’s syndrome or acromegaly. Regular monitoring helps manage blood sugar and prevent complications like nerve damage or heart disease.

Short name

Serum Insulin Level

Frequently asked questions

What Does a High Insulin Level Mean?
High insulin may suggest insulin-producing tumors, insulin resistance, or reactive hypoglycemia. Your doctor will review symptoms and other test results to determine the cause.
What Does a Low Insulin Level Mean?
Low insulin levels often indicate diabetes (either type 1 or type 2) or a deficiency in insulin production. This can lead to dangerously high blood sugar and may require treatment like insulin therapy.
Does Diet or Exercise Affect This Test?
Fasting before the test is critical for accurate results. Exercise or meals can temporarily alter insulin levels, so avoid them unless instructed by your provider.
  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