Proinsulin, Serum/Plasma — Substance Concentration
A blood test that measures proinsulin, a substance made by the pancreas as it produces insulin, to help assess pancreatic beta-cell function.
["Proinsulin is usually interpreted along with insulin and glucose to evaluate how the pancreas is handling insulin production."]
Key facts at a glance
- LOINC
- 65354-3
- Short code
- Proinsulin sp3 p chal SerPl-sCnc
- Synonyms
- Proinsulin sp3 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?
This test measures proinsulin in blood. Proinsulin is an inactive precursor that pancreatic cells convert into insulin, and some proinsulin normally remains in the circulation.
Why might I need this test?
A clinician may order proinsulin when insulin and glucose results do not fully explain symptoms of low blood sugar or when the pancreas's insulin production needs closer evaluation. It may also be used in selected evaluations of insulin-producing tumors or congenital conditions affecting insulin release.
How is the test performed?
A blood sample is collected, and the laboratory measures the amount of proinsulin in serum or plasma. The result is generally reviewed together with glucose, insulin, symptoms, and other relevant findings.
How do I prepare for the test?
No special preparation is universally required, but fasting or timing instructions may be provided because glucose and insulin levels change after eating. Follow the specific instructions from your healthcare professional and tell the laboratory if the test was ordered in relation to a low-blood-sugar episode.
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 elevated proinsulin result can occur when the pancreas has difficulty converting proinsulin into active insulin, when insulin-producing cells are under stress, or in some insulin-producing tumors. It may also be affected by impaired kidney function or changes in blood glucose. A single result does not establish a diagnosis and should be interpreted by a clinician alongside insulin, glucose, symptoms, and other tests.
Short name
Proinsulin
Frequently asked questions
Is proinsulin the same as insulin?
Does a high proinsulin result mean I have diabetes?
Why might proinsulin be checked during a low-blood-sugar evaluation?
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