We will conduct a cross-sectional study of pediatric patients aged 7-18 years. This study will involve recruitment of patients from both the Endocrinology Clinic and the ED. We will recruit patients from the Children's Endocrinology Clinic with well-controlled T1DM, defined as having a hemoglobin A1c <8% at time of the clinic visit, no previous episodes of DKA other than at the time of diagnosis, and no previous hemoglobin A1c values >10%. This study will also involve recruitment of two subsets of patients from the Children's ED: those with DKA and those with T1DM and hyperglycemia without criteria for DKA.