Proinsulin, Serum/Plasma — Substance Concentration
A blood test that measures proinsulin, a precursor of insulin, to help evaluate insulin production and the cause of abnormal glucose levels.
["Proinsulin helps assess how the pancreas produces and releases insulin."]
Key facts at a glance
- LOINC
- 65355-0
- Short code
- Proinsulin sp4 p chal SerPl-sCnc
- Synonyms
- Proinsulin sp4 p chal 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?
A proinsulin test measures proinsulin, a protein made by pancreatic beta cells that is converted into insulin. It is usually measured in a serum or plasma blood sample.
Why might I need this test?
This test may be used to investigate unexplained low or high blood glucose, evaluate insulin production, or help assess the possibility of an insulin-secreting tumor. It is often interpreted with insulin, C-peptide, and glucose results.
How is the test performed?
A blood sample is collected by venipuncture, and the laboratory measures the amount of proinsulin using an immunoassay or another validated laboratory method.
How do I prepare for the test?
Fasting may be required depending on the reason for testing and the laboratory's instructions. Tell your clinician about insulin injections, diabetes medicines, recent hypoglycemia, and any kidney or liver disease before the test.
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.
Elevated proinsulin may occur with impaired insulin secretion, type 2 diabetes, kidney impairment, or an insulin-secreting tumor. It may also be lower when little endogenous proinsulin is being produced, including in some people with type 1 diabetes. Results should be interpreted with glucose, insulin, C-peptide, medications, symptoms, and the laboratory's reference interval.
Short name
Proinsulin
Frequently asked questions
Is proinsulin the same as insulin?
Why are proinsulin, insulin, and C-peptide often checked together?
Can diabetes medicines affect the proinsulin result?
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