C-peptide measured by high-performance liquid chromatography (HPLC) in serum/plasma
This test checks the amount of C-peptide, a natural substance produced by your pancreas along with insulin, to help assess how well your pancreas is making insulin.
["C-peptide helps diagnose and monitor diabetes and pancreatic function."]
Key facts at a glance
- LOINC
- 47586-3
- Short code
- C peptide 1h p Glc SerPl-sCnc
- Synonyms
- C peptide 1h p Glc SerPl-sCnc
- Category
- glucose
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 0.8
- Ref high
- 1.2
- Critical range
- — – 5 N/A
- Fasting
- true
- 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?
Doctors may order this test to diagnose diabetes, especially Type 1 diabetes, where the body doesn’t produce insulin. It can also help determine if insulin is being produced at all, even if blood sugar levels are high. Additionally, it may be used to monitor pancreatic health in people with or without diabetes, such as after a pancreatic surgery or in cases of suspected pancreatic disease.
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 the procedure is quick and typically doesn’t cause discomfort afterward.
What Does the Test Result Mean?
Your result shows the concentration of C-peptide in your blood. While specific ranges can vary by lab, lower than expected levels may suggest insufficient insulin production, while higher levels might indicate overproduction or other conditions. Your doctor will interpret the result in relation to your symptoms and medical history.
What Are Possible Results?
There is no single reference range for C-peptide, as it can vary based on factors like age, health status, and test context. Your doctor will use the result alongside other tests and your medical situation to guide treatment or further testing.
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 levels are critical for diagnosing and managing diabetes. In Type 1 diabetes, C-peptide is almost always low because the pancreas stops producing insulin. In Type 2 diabetes, C-peptide levels may be normal or slightly elevated, depending on how well the pancreas is still producing insulin. It can also help distinguish between insulin-dependent and insulin-independent diabetes. Additionally, C-peptide testing can be useful in evaluating pancreatic function in non-diabetic individuals, such as those with chronic pancreatitis or other pancreatic disorders.
Short name
C-Peptide Level
Frequently asked questions
What does a low C-peptide level mean?
Can C-peptide levels change with diet or exercise?
Is this test the same as checking insulin levels?
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