Question: The surgeon recently saw a 16-year-old patient with underlying diabetes. We weren't sure whether to report the juvenile or adult diabetes code. At what age is the patient an adult instead of a juvenile? Oregon Subscriber Answer: You should not determine the patient's diagnosis based solely on her age. To select the correct diabetes type (type I or type II diabetes mellitus, 250.xx), learn each type's definition and diagnosis requirements. Type I diabetes is an autoimmune disease that destroys the pancreas'beta cells and leads to insulin deficiency. Type II is familial hyperglycemia that occurs primarily in adults but can also occur in children and adolescents. This form of diabetes results from an insulin resistance with a multiple etiology and is not totally understood. Gestational diabetes is any degree of glucose intolerance with onset or first recognition during pregnancy. The terms "adult-onset" and "juvenile" are fairly irrelevant when determining which type of diabetes a patient has, because people of all ages can be diagnosed with type II diabetes (adult-onset type). When in doubt, ask your physician to be sure you are assigned the correct diagnosis, and encourage him to document in the future whether patients have type I or type II.