Peptide fragment analysis of proinsulin (Serum/Plasma)
This test measures the ratio of two forms of insulin-like molecules in your blood. It helps assess how well your pancreas produces insulin and may be used to evaluate diabetes management or beta-cell function.
["This test helps monitor how your body processes insulin and supports diabetes care."]
Key facts at a glance
- LOINC
- 50462-1
- Short code
- C peptide sp2 SerPl-sCnc
- Synonyms
- C peptide sp2 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 Is This Test Done?
Your healthcare provider may order this test if you have diabetes, are at risk for diabetes, or if you’re being evaluated for conditions affecting insulin production or metabolism. It can also help determine how well your current diabetes treatment is working.
What Does This Test Measure?
The test compares two parts of proinsulin—a precursor to insulin. Normally, your pancreas converts most proinsulin into insulin, but if this process is disrupted, the ratio of these fragments can change. Higher ratios may suggest inefficient insulin production or other metabolic issues.
Sample Collection and Preparation
A blood sample is drawn from a vein, usually in your arm. The sample is collected in a tube that separates serum or plasma from blood cells. This test is typically done after fasting, but your provider will confirm timing with you.
How Results Are Interpreted
Results are expressed as a ratio (e.g., peptide fragment A to peptide fragment B) rather than absolute values. While reference ranges vary by lab, abnormal ratios may signal problems like insulin resistance, diabetes complications, or other endocrine disorders.
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.
Abnormal results may indicate underlying issues such as impaired insulin processing, diabetes-related complications, or conditions affecting pancreatic function. This test is often used alongside other glucose-related tests to provide a more complete picture of metabolic health.
Short name
Proinsulin Peptide Ratio
Frequently asked questions
What does a high or low ratio mean?
How often should I get this test?
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