Fulminant type 1 diabetes is characterized by almost complete β-cell destruction, resulting in scarce insulin secretion. In the present study, we aimed to clarify clinical features related to serum C-peptide levels measured by a high sensitivity method, chemiluminescent enzyme immunoassay, in 12 patients with fulminant type 1 diabetes. Serum C-peptide was detected (0.007-0.10 nmol/L) in four patients and was not detected in eight patients. A negative correlation was observed between serum C-peptide levels and daily dosages of insulin (P < 0.01). The patients with detectable C-peptide showed a significantly lower M-value than those without (P = 0.01). In conclusion, our present results suggest that even very low levels of endogenous insulin secreting capacity can improve daily dosages of insulin and stabilize blood glucose levels. (J Diabetes Invest, doi: 10.1111/j.2040-1124.2010.0059.x, 2010).
Keywords: Fulminant type 1 diabetes; M‐value; Serum C‐peptide.