Insulin, Serum/Plasma — Substance Concentration
Measures insulin in serum or plasma to help evaluate blood sugar control, diagnose diabetes, and investigate unexplained low blood sugar.
["An insulin blood test helps clinicians assess how the body regulates blood sugar."]
Key facts at a glance
- LOINC
- 14293-5
- Short code
- Insulin BS SerPl-sCnc
- Synonyms
- Insulin BS 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 blood test measures the amount of insulin, a hormone made by the pancreas, in serum or plasma. Insulin helps glucose enter cells for energy and helps keep blood sugar within a healthy range.
Why might I need this test?
Your clinician may order this test when evaluating diabetes, insulin resistance, unexplained low blood sugar, or symptoms that can occur with abnormal insulin levels. It may also be used to monitor certain diabetes treatments.
How is the test performed?
A blood sample is collected, usually by venipuncture, and the insulin level is measured in the laboratory using an immunoassay-based method. The sample is then analyzed as a serum or plasma substance concentration.
How do I prepare for the test?
This test is often performed while fasting, so follow your clinician's instructions about eating and drinking beforehand. Tell your clinician about insulin injections, diabetes medicines, supplements, recent illness, and any symptoms of low blood sugar.
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.
An insulin level that is higher than expected may occur with insulin resistance, obesity, or type 2 diabetes, especially when interpreted alongside glucose and other tests. A lower-than-expected level, particularly with low blood sugar, may suggest inadequate insulin production or excess insulin effect. Results depend on fasting status, timing, medications, and the laboratory's reference interval, so they should be interpreted by a clinician.
Short name
Insulin
Frequently asked questions
Do I need to fast before this test?
Is this the same as a home blood glucose test?
Can I take my diabetes medicines 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