Insulin, Serum/Plasma — Substance Concentration
Measures the amount of insulin in a blood sample to help assess how the body regulates blood glucose.
["An insulin blood test is usually interpreted together with glucose levels to evaluate insulin production and glucose regulation."]
Key facts at a glance
- LOINC
- 25691-7
- Short code
- Insulin sp1 p chal SerPl-sCnc
- Synonyms
- Insulin sp1 p chal SerPl-sCnc
- 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 insulin, a hormone made by the pancreas that helps cells take up glucose from the blood. It is performed using a serum or plasma blood sample.
Why might I need this test?
Your clinician may order this test when investigating high or low blood glucose, diabetes, insulin resistance, or symptoms related to abnormal insulin levels. It may also be measured during a glucose tolerance test or when evaluating how the body responds to a meal or glucose challenge.
How is the test performed?
A blood sample is drawn from a vein and placed in a collection tube. The laboratory measures the insulin concentration in the serum or plasma, often using an immunoassay.
How do I prepare for the test?
If your clinician requested a fasting test, follow their instructions, which may include avoiding food and drinks other than water for the specified period. If the test is part of a glucose tolerance test, follow the exact timing and preparation instructions provided.
Reference range
Fasting: 2.6-24.9 μIU/mLN/A
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.
Insulin results must be interpreted with the accompanying glucose level, meal or glucose-challenge timing, medications, and clinical findings. Higher-than-expected insulin may occur with insulin resistance or hyperinsulinemia, while lower-than-expected insulin may indicate inadequate insulin production. Abnormal results do not by themselves diagnose a specific condition and should be reviewed by your clinician.
Short name
Insulin
Frequently asked questions
Is a fasting blood sample required for an insulin test?
Why is my insulin result checked with glucose?
Does a high insulin level always mean I have diabetes?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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