Insulin, Serum/Plasma — Substance Concentration
A blood test that measures insulin in serum or plasma, helping assess pancreatic insulin production and insulin resistance.
["Insulin testing helps evaluate how the body regulates blood glucose, usually alongside glucose measurements."]
Key facts at a glance
- LOINC
- 25688-3
- Short code
- Insulin sp13 p chal SerPl-sCnc
- Synonyms
- Insulin sp13 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 the amount of insulin in a blood sample. Insulin is a hormone made by the pancreas that helps cells take up glucose for energy.
Why might I need this test?
Your clinician may order insulin testing to investigate low or high blood glucose, evaluate diabetes or insulin resistance, or assess how the pancreas responds to glucose. It may be measured while fasting, after a meal, or during a glucose challenge, depending on the test.
How is the test performed?
Blood is collected from a vein and placed in a tube. The laboratory measures the insulin concentration in the serum or plasma. If this is part of a glucose challenge, samples may be collected at several specified times.
How do I prepare for the test?
Follow your clinician's instructions about fasting and the timing of the blood draw. Keep meals, drinks, exercise, and diabetes medications consistent unless your care team tells you to change them.
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 glucose levels, symptoms, medications, and the timing of the sample. Higher insulin values may occur with insulin resistance, obesity, metabolic syndrome, or type 2 diabetes, while lower values may occur when the pancreas does not produce enough insulin, as in type 1 diabetes. Results collected during a glucose challenge reflect the body's response to that challenge rather than fasting levels alone.
Short name
Insulin
Frequently asked questions
Does this test show whether I have diabetes?
Do I need to fast for an insulin blood test?
Can I take my diabetes medication before the test?
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