Insulin Type, Serum/Plasma — Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
Measures insulin in serum or plasma and characterizes the insulin present, which may help evaluate insulin production or identify an injected insulin form.
["This test measures insulin and may help identify whether the insulin present is naturally produced or comes from an injected medication."]
Key facts at a glance
- LOINC
- 97004-6
- Short code
- Insulin Type SerPl LC/MS/MS
- Synonyms
- Insulin Type SerPl LC/MS/MS
- 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 test measures insulin in a serum or plasma sample. Liquid chromatography-tandem mass spectrometry, or LC-MS/MS, separates and identifies insulin so the laboratory can quantify it and, when appropriate, determine the type of insulin present.
Why might I need this test?
A clinician may order this test to investigate unusually low or high glucose, symptoms that suggest excess insulin, or suspected insulin injection or use of an insulin analog. The test may also be used when there is concern that an unexpected insulin form is affecting a person's glucose levels.
How is the test performed?
A blood sample is collected and prepared as serum or plasma. The laboratory then analyzes it with LC-MS/MS to measure insulin and characterize the insulin form detected.
How do I prepare for the test?
Follow your clinician's instructions about fasting and the timing of the blood draw. Do not stop insulin or other medicines unless your clinician tells you to. If you recently received insulin, tell the laboratory the type, dose, and exact time because this can affect the results.
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 unexpectedly high insulin level may occur with excess insulin production, insulin resistance, obesity, or recent injection of insulin, depending on the clinical situation. Insulin that is higher than expected alongside low glucose can raise concern for excess insulin in the bloodstream. Results must be interpreted with glucose levels, symptoms, medication history, and other tests; this result alone does not diagnose diabetes or an insulin-producing tumor.
Short name
Insulin Type, LC-MS/MS
Frequently asked questions
Does this test require fasting?
Can this test diagnose diabetes?
Why does the laboratory report the type of insulin?
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