C-peptide measured by high-performance liquid chromatography (HPLC) in plasma
This test measures the amount of C-peptide, a natural byproduct of insulin production, in your blood. It helps assess how well your pancreas is producing insulin.
["C-peptide levels can indicate insulin function and help diagnose diabetes or other endocrine conditions."]
Key facts at a glance
- LOINC
- 13043-5
- Short code
- C peptide 3h p chal SerPl-mCnc
- Synonyms
- C peptide 3h p chal 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 healthcare provider may order a C-peptide test to evaluate insulin production, diagnose diabetes (such as type 1 or type 2), or monitor conditions like insulinoma (a rare tumor affecting insulin). It can also help distinguish between types of diabetes or assess how your body responds to insulin therapy.
How Is the Sample Collected?
A blood sample is taken from a vein, usually in your arm. The blood is collected in a special tube to separate plasma from other components before testing.
What Should You Expect Before the Test?
No special preparation is typically needed, but you may be asked to fast for a few hours before the test if instructed by your provider. Avoid smoking or caffeine for 30 minutes before the draw.
What Does the Test Result Mean?
Results are compared to reference ranges for healthy individuals, but exact values can vary by lab. High levels may suggest overproduction of insulin, while low levels could indicate insufficient insulin production or other metabolic issues.
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.
◆Associated findings1
Short name
C-peptide (HPLC)
Frequently asked questions
What is C-peptide, and why is it measured?
How does C-peptide differ from insulin testing?
Can diet or fasting affect C-peptide results?
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