C Peptide testing - odd result

EllieM said:

My understanding is that non fasting cpeptide can be many multiples of fasting cpeptide, so I don't think you can compare the two results.

https://emedicine.medscape.com/article/2087824-overview?form=fpf

C-peptide is a peptide composed of 31 amino acids. It is released from the pancreatic beta cells during cleavage of insulin from proinsulin. It is mainly excreted by the kidney, and its half-life is 3-4 times longer than that of insulin.


The reference ranges for C-peptide are as follows

• Fasting: 0.78-1.89 ng/mL or 0.26-0.62 nmol/L (SI units)
• 1 hour after glucose load: 5-12 ng/mL

I think you need to ask your endocrinologist to clarify. what your figures mean. Given that T1s and T3cs have issues with lack of insulin, I'm guessing a high cpeptide is a good sign for you, though I'm not sure that double the upper level for a fasting test is actually high if you weren't fasting.

Click to expand...