C-peptide (Serum) with Mass Concentration Measurement
This test measures the amount of C-peptide, a small protein produced along with insulin in your pancreas. It helps assess how much insulin your body naturally makes.
["C-peptide helps doctors check insulin production and diagnose conditions like diabetes."]
Key facts at a glance
- LOINC
- 47587-1
- Short code
- C peptide 1M p Glc SerPl-sCnc
- Synonyms
- C peptide 1M 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 evaluate your pancreas’s ability to produce insulin. It can help diagnose type 1 or type 2 diabetes, check for insulin resistance, or monitor treatment for conditions like diabetes or pancreatic issues. C-peptide levels can also help distinguish between insulin-dependent and insulin-independent diabetes.
What Does the Test Involve?
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 concentration. No special preparation is needed, but fasting may be required depending on the clinical context.
What to Expect Before the Test
You may be asked to fast for a few hours before the test if it’s part of a glucose tolerance or insulin sensitivity study. Otherwise, you can eat and drink normally unless instructed otherwise. Wear comfortable clothing and bring any medications you’re currently taking.
What to Expect During the Test
The test involves a quick needle insertion to draw blood. You may feel a slight pinch, but it usually doesn’t cause discomfort. The process takes only a few minutes, and you can resume your normal activities afterward.
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 important because they reflect your natural insulin production. Low levels may indicate insufficient insulin production (e.g., type 1 diabetes), while high levels could suggest overproduction or resistance. Doctors use this test to confirm diabetes diagnosis, assess insulin deficiency, or evaluate treatment effectiveness in conditions like diabetes or pancreatic disorders.
Short name
C-peptide level
Frequently asked questions
What does a C-peptide test tell me about my diabetes?
How is C-peptide different from insulin?
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