C-peptide (Serum) – Quantitative
This test measures the amount of C-peptide, a small protein produced by your pancreas along with insulin during digestion. It helps assess how well your pancreas is producing insulin naturally.
["C-peptide helps diagnose and monitor diabetes and pancreatic function."]
Key facts at a glance
- LOINC
- 95076-6
- Short code
- C peptide 15M p meal SerPl-mCnc
- Synonyms
- C peptide 15M p meal SerPl-mCnc
- Category
- coagulation
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 0.8
- Ref high
- 1.2
- Critical range
- — – 5 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 85610
- SNOMED
- 396252006
- 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
Why Is This Test Done?
Your doctor may order this test to check if your pancreas is making enough insulin naturally. It’s often used to diagnose type 1 diabetes, type 2 diabetes, or to evaluate how well insulin therapy is working. C-peptide levels can also help distinguish between insulin-dependent and insulin-independent diabetes.
How Is the Sample Collected?
A blood sample is taken from a vein, usually in your arm. You may feel a small pinch when the needle is inserted, but it typically only takes a few seconds. The blood is then sent to a lab for testing.
What Does the Test Result Mean?
Results are interpreted by your healthcare provider based on your medical history and symptoms. High levels may indicate healthy insulin production, while low levels could suggest diabetes or other pancreatic issues. No specific reference ranges are provided here, as they vary by lab and clinical context.
Common Reasons for Testing
Doctors may recommend this test if you have symptoms of diabetes, such as frequent urination, extreme thirst, unexplained weight loss, or fatigue. It’s also used in research or clinical settings to monitor insulin production in people with diabetes or those undergoing insulin therapy.
Reference range
INR: 0.8-1.2 (warfarin: 2.0-3.0)N/A
Inform your healthcare provider if you are taking blood thinners. No special preparation required.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
C-peptide testing is critical for diagnosing diabetes because it provides a more accurate picture of your body’s natural insulin production. Unlike insulin levels, which can be affected by recent insulin use, C-peptide reflects your pancreas’s ability to produce insulin independently. This helps doctors tailor treatment plans and avoid over- or under-medication.
Short name
C-peptide level
Frequently asked questions
What causes abnormal C-peptide levels?
How long does it take to get results?
Can I eat or drink 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