COMMENTS AND RESPONSES Comment on: Besser et al. Lessons From theMixed-Meal Tolerance Test: Use of 90-Minute and Fasting C-Peptide in Pediatric Diabetes.

I t was extremely gratifying to read aninteresting article in Diabetes Care byBesser et al. (1) that suggested that 90-min C-peptide is a highly sensitive and specific measure of area under curve and peak C-peptide in children and ado-lescents with type 1 diabetes and offers a practical alternative to a full mixed-meal tolerance test. The authors also suggested that C-peptide measured at diagnosis and age at diagnosis can be used to predict the time taken for patients to become insulin-deficient. The authors suggested that those with the lowest tertile of fasting C-peptide (,0.17 nmol/L) reached insulin defi-ciency quicker than those in the highest tertile of fasting C-peptide ($0.29 nmol/L