C-peptide result checker — type 1 vs type 2 diabetes
Enter your fasting C-peptide to see what it says about how much insulin your pancreas is still making — and whether the picture fits type 1, type 2, or the often-missed LADA.
— nmol/L
Medical disclaimer: This calculator is for general educational purposes only and does not constitute medical advice or a diagnosis. Results are estimates based on the values you enter and standard formulas and reference ranges, which vary between laboratories and between individuals. Always discuss your results with a qualified healthcare professional. If you are experiencing a medical emergency, call 9-1-1.
Why C-peptide matters. C-peptide is released in equal amounts to insulin, so it shows how much insulin your own pancreas is still making. Low levels point toward type 1 diabetes (autoimmune beta-cell loss); normal-to-high levels point toward type 2 / insulin resistance. It is key to spotting LADA — a slow-onset autoimmune diabetes in adults that is frequently misdiagnosed as type 2 and under-treated for years.
Get an endocrinologist to review your diabetes type — $45
Upload your C-peptide, glucose, HbA1c and antibody results and get a written opinion from a PGIMER/AIIMS-trained endocrinologist within 6 hours — what your results suggest about diabetes type and treatment. No referral needed.
Frequently asked questions
What is a normal fasting C-peptide?
A common fasting reference range is about 0.37–1.47 nmol/L, though ranges vary by laboratory. Low levels suggest reduced insulin production (type 1 or advanced type 2); normal-to-high levels suggest preserved production with insulin resistance (type 2).
What is LADA and why is it missed?
LADA (latent autoimmune diabetes in adults) is a slowly-progressing autoimmune diabetes that appears in adulthood. Because it looks like type 2 at first, it is often misdiagnosed and treated with oral agents for years before insulin is started. A low-ish C-peptide with positive antibodies is a clue.
Can Ginie Health help clarify my diabetes type?
Yes. A written opinion from a PGIMER/AIIMS-trained endocrinologist costs $45 CAD, delivered within 6 hours, with no referral needed — useful for interpreting C-peptide with your antibodies and glucose.