Proinsulin, Serum/Plasma — 2-Hour Post-Challenge, Substance Concentration
Measures proinsulin in blood 2 hours after a glucose challenge to help assess how the pancreas produces and releases insulin.
["This timed blood test can show whether abnormal insulin production or release is contributing to changes in blood sugar."]
Key facts at a glance
- LOINC
- 65353-5
- Short code
- Proinsulin sp2 p chal SerPl-sCnc
- Synonyms
- Proinsulin sp2 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?
Proinsulin is an inactive precursor that the pancreas converts into insulin. This test measures proinsulin in serum or plasma 2 hours after a standardized glucose challenge.
Why might I need this test?
Your clinician may order this test with other glucose-tolerance measurements to evaluate pancreatic insulin production and release. It may be used when diabetes, insulin resistance, or symptoms of low blood sugar are being investigated.
How is the test performed?
After an overnight fast, a blood sample is collected and you are given a glucose drink. A second blood sample is then taken at the specified time, usually 2 hours later, to measure how your body responds.
How do I prepare for the test?
Follow the clinic's instructions, which may include fasting for 8 to 12 hours and drinking only plain water. Take medicines and diabetes treatments as directed, and tell your clinician if you become ill or your blood sugar falls during 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.
Proinsulin that remains elevated after a glucose challenge may indicate difficulty converting proinsulin into active insulin or abnormal insulin release, which can occur with diabetes or insulin resistance. Elevated results must be interpreted with the glucose measurements, symptoms, medications, and other pancreatic tests. An elevated fasting proinsulin level in someone with recurrent hypoglycemia may prompt further evaluation for an insulin-secreting tumor, but it does not establish that diagnosis by itself.
Short name
2-Hour Post-Challenge Proinsulin
Frequently asked questions
Is this the same as an insulin test?
Do I need to fast before this test?
Can I take my medicines before the 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