Intact Insulin, Serum — Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS), Concentration
Measures intact insulin in a blood sample using LC-MS/MS, a method that can distinguish insulin from related forms such as proinsulin.
["This test measures circulating intact insulin and is most useful when interpreted alongside blood glucose and other clinical findings."]
Key facts at a glance
- LOINC
- 89324-8
- Short code
- Insulin intact Ser LC/MS/MS-aCnc
- Synonyms
- Insulin intact Ser LC/MS/MS-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
- Method
- lc-ms-ms
- 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 concentration of intact insulin, the hormone that helps glucose enter cells for energy. LC-MS/MS separates and identifies insulin-related molecules with high analytical specificity.
Why might I need this test?
A clinician may order this test to investigate unusually high or low insulin levels, unexplained changes in blood glucose, or possible use of insulin medication. It is often evaluated together with a simultaneous glucose test.
How is the test performed?
A blood sample is collected, usually from a vein, and the serum is analyzed using liquid chromatography-tandem mass spectrometry. No special preparation is required for the blood collection itself.
How do I prepare for the test?
Fasting may be required, especially when insulin is being compared with blood glucose. Follow the laboratory's instructions, and if instructed to fast, drink only plain water and avoid food, beverages, gum, and smoking for the specified period.
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.
Low insulin, particularly when accompanied by elevated glucose, may indicate insufficient insulin production or use of glucose-lowering medicines. Higher insulin levels can occur with insulin resistance or after administered insulin, so results must be interpreted with glucose, symptoms, medications, and other tests.
Short name
Intact insulin
Frequently asked questions
Does this test include proinsulin?
Why is insulin measured at the same time as glucose?
Does a low insulin result always mean 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