Insulin, Serum/Plasma — Concentration
This blood test measures the amount of insulin circulating in the body. It may be used with glucose testing to help evaluate blood sugar regulation.
["An insulin blood test helps assess how well the body is regulating blood sugar."]
Key facts at a glance
- LOINC
- 33818-6
- Short code
- Insulin sp8 p chal SerPl-aCnc
- Synonyms
- Insulin sp8 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
What is this test?
This test measures insulin in blood drawn from a vein. Insulin is a hormone made by the pancreas that helps glucose move into cells for energy.
Why might I need this test?
Your clinician may order insulin testing to investigate symptoms of high or low blood sugar, monitor diabetes treatment, or evaluate how the body responds to food or glucose. It is often interpreted together with a glucose measurement taken at the same time.
How is the test performed?
A blood sample is collected by needle, usually from a vein in the arm, and sent to a laboratory for analysis. The results are reported as a concentration and are reviewed with other blood sugar tests.
How do I prepare for the test?
Follow your clinician's instructions about fasting and medication timing. Some insulin tests are performed while fasting, while others are timed after food or a glucose challenge, so the preparation can affect the result.
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 levels may be higher or lower than expected when blood sugar regulation is abnormal. Results can be affected by blood glucose at the time of the test, recent meals, stress, illness, and medicines such as insulin or diabetes medications. Insulin should therefore be interpreted alongside glucose and other findings rather than used alone to make a diagnosis.
Short name
Insulin
Frequently asked questions
Does this test diagnose diabetes?
Do I need to fast before an insulin test?
Why are insulin and glucose often tested together?
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