Metabolic
C-Peptide
LOINC 1986-9 · ng/mL
Ranges
Reference range: 0.8–3.85 ng/mL
What it is
C-peptide is released in equal amounts to insulin when your pancreas makes it, so it shows how much insulin your body is producing.
Why it matters
It helps distinguish how much insulin you make yourself, useful in assessing diabetes and low blood sugar.
What high values can mean
A higher value suggests your pancreas is making a lot of insulin, as in insulin resistance or type 2 diabetes.
What low values can mean
A lower value suggests reduced insulin production, as can happen in type 1 diabetes.
How to improve it
Where related to insulin resistance, weight management, activity and diet can improve the underlying picture.
Food & lifestyle
A balanced diet lower in refined carbs, plus regular activity, supports healthier insulin and blood-sugar control.
Preparing for the testFasting required
Often measured fasting and sometimes with a glucose sample — follow your lab's instructions.
When to talk to a doctor
Interpreted by a doctor with your glucose and clinical history to understand insulin production.
Related markers
Sources
- MedlinePlus (NIH)
- Testing.com (AACC)
Content reviewed on June 26, 2026
Medical disclaimer
This content is for educational purposes only. It is not medical advice and does not diagnose, treat, or prevent any condition. Reference ranges vary between laboratories — always use the range printed on your report and discuss your results with a healthcare professional.
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