Proinsulin, Serum/Plasma — 3-Hour Post-Challenge Substance Concentration
Measures proinsulin, a precursor of insulin, in a blood sample. It may be used with insulin and C-peptide to evaluate how the body produces and processes insulin.
["Proinsulin helps assess insulin production and processing, especially when interpreted alongside insulin and C-peptide results."]
Key facts at a glance
- LOINC
- 27857-2
- Short code
- Proinsulin 3h p chal SerPl-sCnc
- Synonyms
- Proinsulin 3h 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 blood test measures proinsulin, a prohormone that is converted into insulin and C-peptide. Proinsulin testing can provide information about pancreatic insulin production and processing.
Why might I need this test?
A clinician may order this test when evaluating diabetes, unexplained low blood sugar, or other conditions involving insulin. It is usually interpreted with insulin and C-peptide measurements because those tests help distinguish different causes of abnormal results.
How is the test performed?
A blood sample is collected from a vein and analyzed in the laboratory. If this is a timed post-challenge test, the sample must be collected at the specified time after the challenge, such as a glucose-containing drink.
How do I prepare for the test?
Follow the laboratory or clinician's instructions exactly. You may need to fast or avoid exercise beforehand, and if a timed challenge is involved, you should remain at the testing site and follow the preparation and timing instructions provided.
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 when insulin production or processing is impaired and may be associated with high insulin levels or reduced kidney function. Low proinsulin may be seen with low endogenous insulin production or after insulin therapy. Results should be interpreted with insulin, C-peptide, glucose, symptoms, and other relevant findings.
Short name
Proinsulin
Frequently asked questions
Is proinsulin the same as insulin?
Why are insulin, C-peptide, and proinsulin often checked together?
Do I need to fast before this 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