C-Peptide, 24-Hour Urine, Rate Measurement
This test measures the rate at which C-peptide is excreted in urine collected over a full 24-hour period, which helps evaluate how well your pancreas is producing insulin.
["A 24-hour urine C-peptide rate gives your care team a view of your body's insulin production over a full day."]
Key facts at a glance
- LOINC
- 25358-3
- Short code
- C peptide 24h Ur-sRate
- Synonyms
- C peptide 24h Ur-sRate
- Category
- coagulation
- Sample
- urine
- Container
- Sterile urine container
- 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
- 10 mL
- Stability
- Room temperature: 2h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 4–24 hours
- Order
- routine
What Is C-Peptide?
C-peptide is a small protein released by the pancreas at the same time as insulin. Because insulin is cleared from the blood quickly and C-peptide lasts longer, measuring C-peptide gives a more stable picture of how much insulin your body is making on its own.
Why Collect Urine for 24 Hours?
A single blood sample shows C-peptide at one moment. Collecting all urine over 24 hours captures the total amount produced across the day, which can smooth out normal ups and downs and reflect overall pancreatic output.
How the Collection Works
You will be given a container and instructions to collect every urine sample for a full 24-hour period, usually starting after the first morning void is discarded. The laboratory measures the total C-peptide in the collection and relates it to the collection time to report a rate.
What the Results Can Mean
Low C-peptide output can suggest the pancreas is making little insulin, while higher output can occur when the body makes more insulin than usual. Your clinician interprets the rate alongside your symptoms, other tests, and medications, since results vary between people and laboratories.
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
24-hr Urine C-Peptide Rate
Frequently asked questions
Do I need to change my diet or medications before this test?
What happens if I miss a urine sample during collection?
Does a high or low result always mean I have a disease?
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