C-peptide measured by high-performance liquid chromatography (HPLC) in serum/plasma
This test checks the amount of C-peptide, a natural substance produced along with insulin in your pancreas. It helps assess how well your pancreas is making insulin.
["C-peptide helps evaluate your body’s insulin production independently of external insulin use."]
Key facts at a glance
- LOINC
- 58517-4
- Short code
- C peptide 4h p Glc SerPl-sCnc
- Synonyms
- C peptide 4h 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?
Your doctor may order this test to diagnose or monitor conditions like diabetes, especially Type 1 diabetes, where the body doesn’t produce insulin. It can also help determine if insulin is being produced naturally or if external insulin is needed. Sometimes, it’s used to check how well your pancreas is working after a pancreas transplant or surgery.
What does the result mean?
A result that is too high or too low compared to what’s expected can indicate problems with insulin production. For example, low levels might suggest your body isn’t making enough insulin, while high levels could be seen in certain metabolic conditions or after certain treatments.
How is the test performed?
A blood sample is taken from a vein, usually in your arm. The sample is then sent to a lab where it’s analyzed using high-performance liquid chromatography (HPLC) to measure C-peptide levels accurately.
What should I expect before or after the test?
There are usually no special preparations needed for this test. You may feel slight discomfort from the needle, but it’s a quick and common procedure. Afterward, you can resume your normal activities. If you’re on blood thinners or have a bleeding disorder, let your doctor know before the test.
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 is a biomarker for insulin production. It helps differentiate between Type 1 and Type 2 diabetes, assesses insulin independence in diabetes management, and evaluates pancreatic function post-surgery or transplant. Abnormal levels may also indicate conditions like pancreatic tumors or metabolic disorders.
Short name
C-peptide (HPLC)
Frequently asked questions
What does a C-peptide test tell me about my diabetes?
How is C-peptide different from insulin?
Can C-peptide test results change over time?
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