C Peptide Calculator Form
Example Data Table
| Scenario | C peptide | Glucose | CPGR x 100 | Interpretation |
|---|---|---|---|---|
| Low secretion | 0.3 ng/mL | 92 mg/dL | 0.326 | Reduced endogenous secretion is possible. |
| Preserved function | 1.4 ng/mL | 95 mg/dL | 1.474 | Beta-cell reserve appears maintained. |
| High output | 3.8 ng/mL | 108 mg/dL | 3.519 | Insulin resistance or reduced clearance may exist. |
Formula Used
Unit conversion: 1 nmol/L of c peptide is approximately 3.0 ng/mL.
Glucose conversion: mmol/L = mg/dL / 18.
C peptide to glucose ratio: CPGR x 100 = (c peptide in ng/mL / glucose in mg/dL) x 100.
Modified ratio: c peptide in nmol/L / glucose in mmol/L.
Beta-cell proxy: 20 x c peptide in nmol/L / (glucose in mmol/L - 3.5).
These equations support screening. They do not replace clinical diagnosis, stimulated testing, or direct physician review.
How to Use This Calculator
- Enter the measured c peptide result.
- Select the reported c peptide unit.
- Enter the paired glucose value from the same sample.
- Select the glucose unit for automatic conversion.
- Add weight, height, and creatinine if you want more context.
- Press Calculate to show the result section above the form.
- Use Download CSV or Download PDF for sharing and records.
Important Medical Note
C peptide interpretation depends on fasting state, renal function, diabetes type, treatment history, and laboratory range. This tool is educational and should support, not replace, clinician judgment.