Insulin, Serum/Plasma — Mass Concentration
A blood test that measures the amount of insulin, often alongside glucose, to assess how the body regulates blood sugar.
["Insulin results are most useful when interpreted with glucose levels, the reason for testing, and the timing of the blood draw."]
Key facts at a glance
- LOINC
- 12741-5
- Short code
- Insulin sp4 p chal SerPl-mCnc
- Synonyms
- Insulin sp4 p chal SerPl-mCnc
- 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, in blood. Insulin helps glucose enter cells for energy and helps keep blood glucose within a controlled range.
Why might I need this test?
A clinician may order insulin with a glucose test to evaluate fasting blood sugar, insulin resistance, or how the pancreas responds to a glucose load. It may also be used when unexplained low blood sugar is suspected.
How is the test performed?
A blood sample is collected from a vein and analyzed in the laboratory. If insulin is measured during a glucose tolerance test, blood may be drawn more than once at specified times after glucose is given.
How do I prepare for the test?
Fasting may be required, so follow the preparation instructions provided by the laboratory or clinician. Do not stop diabetes medicines or change their schedule unless your healthcare professional specifically directs you to do so.
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 that is higher than expected may occur with insulin resistance, metabolic syndrome, or type 2 diabetes, particularly when glucose is also elevated. Insulin that is lower than expected may reflect reduced pancreatic insulin production, prolonged fasting, or certain medicines. Results should be interpreted together with glucose levels, symptoms, medications, and the timing of the specimen.
Short name
Insulin
Frequently asked questions
Is a fasting insulin test the same as an insulin tolerance test?
Why are insulin and glucose often tested together?
Do I need to stop taking 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