C-peptide (Serum or Plasma) Concentration
This test measures the amount of C-peptide, a natural substance produced by your pancreas along with insulin, in your blood. It helps assess how well your pancreas is producing insulin.
["C-peptide helps diagnose and monitor diabetes and pancreatic function."]
Key facts at a glance
- LOINC
- 77612-0
- Short code
- C peptide 45M p chal SerPl-sCnc
- Synonyms
- C peptide 45M p chal SerPl-sCnc
- 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
What Is C-Peptide Used For?
C-peptide is primarily used to evaluate your body’s natural insulin production. Unlike insulin, which can be affected by medications or other factors, C-peptide reflects your pancreas’s ability to produce insulin independently. This can be especially useful in diagnosing type 1 diabetes, where the pancreas produces little to no insulin, or in assessing pancreatic health in other conditions.
How Is the Test Performed?
A blood sample is taken from a vein, usually in your arm. The sample is sent to a lab where it is analyzed to measure C-peptide levels. The test does not require fasting unless specified by your healthcare provider.
Why Might You Need This Test?
Your doctor may order a C-peptide test if you have symptoms of diabetes, unexplained weight loss, or if you’re being evaluated for conditions affecting your pancreas, such as pancreatitis or pancreatic cancer. It can also help monitor diabetes treatment effectiveness.
What Do Results Mean?
High or low C-peptide levels can indicate different health conditions. For example, very low levels may suggest type 1 diabetes, while normal or high levels could help rule out diabetes or assess pancreatic function in other contexts. Your doctor will interpret results in relation to your medical history.
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.
Clinical Significance: C-peptide levels provide critical insights into insulin production and pancreatic health. Elevated levels may indicate insulin resistance or overproduction, while low levels often point to insufficient insulin secretion, such as in type 1 diabetes. This test can also help differentiate between types of diabetes or rule out other pancreatic disorders.
Short name
C-peptide test
Frequently asked questions
What does a C-peptide test tell me about my diabetes?
How often should I get this test?
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