C-peptide (Serum or Plasma) with High-Performance Liquid Chromatography (HPLC) Measurement
This test measures the amount of C-peptide, a byproduct of insulin production, in your blood. It helps assess how well your pancreas is making insulin.
["C-peptide helps evaluate insulin production and diabetes management."]
Key facts at a glance
- LOINC
- 57651-2
- Short code
- C peptide 1.3h p chal SerPl-sCnc
- Synonyms
- C peptide 1.3h 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
Why This Test Is Done
Doctors may order a C-peptide test to diagnose or monitor diabetes, especially type 1 or type 2 diabetes. It can also help determine whether insulin is being produced naturally or if insulin therapy is needed. Additionally, it may be used to check for conditions like pancreatic diseases or to evaluate how well a person’s pancreas is functioning after surgery or treatment for diabetes.
How the Test Works
Blood is drawn from a vein in your arm. The sample is then processed to separate the serum or plasma, which is analyzed using HPLC to measure C-peptide levels. This method ensures accurate detection of small amounts of C-peptide in your bloodstream.
What to Expect Before the Test
No special preparation is usually needed, but you may be asked to fast for a few hours before the test if instructed by your healthcare provider. Wear comfortable clothing and bring any necessary medications.
What to Expect During the Test
You’ll lie down comfortably while a healthcare professional inserts a needle into your arm. A small amount of blood is collected into a tube. The process is quick and typically painless, though some people may feel a brief pinch.
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.
A C-peptide test is crucial for diagnosing diabetes, particularly type 1 diabetes, where the pancreas produces little to no insulin. High levels may indicate normal insulin production, while low levels suggest insulin deficiency. It can also help differentiate between type 1 and type 2 diabetes and assess the effectiveness of insulin therapy in managing blood sugar levels.
Short name
C-peptide test
Frequently asked questions
What does a C-peptide test tell me about my diabetes?
How does this test differ from checking my blood sugar levels?
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