C-peptide in DM

C-peptide is formed during conversion of pro-insulin to insulin. It is used to distinguish between exogenous and endogenous circulating insulin. C-peptide will not rise in Pt who develops hypoglycemia from exogenous insulin.

• • Insulin/C-peptide ratio <1 = increase in endogenous insulin secretion

  • Insulin/C-peptide ratio >1 = exogenous insulin