<prompt> The diagnosis of diabetes mellitus is certain in which of the following situations?Abnormal oral glucose tolerance in a 24-yrs-old woman who has been dietingSuccessive fasting plasma glucose concentrations of 8, 9, and 8.5 mmolL in an asymptomatic, otherwise healthy businesswomanA serum glucose level 7.8 mmolL in a woman in her twenty-fifth week of gestation after a 50-g oral glucose loadPersistent asymptomatic glycosuria in a 30-yrs-old woman  <response>: The occurrence of hyperglycemic ketoacidosis or hyperglycemic hyperosmolar coma is diagnostic of diabetes mellitus. Similarly, persistent fasting hyperglycemia , even if it is asymptomatic, has been recommended by the National Diabetes Data Group as a criterion for the diagnosis of diabetes. However, abnormal glucose tolerance-whether after eating or after a standard glucose tolerance test -can be caused by many factors e.g., anxiety, infection or other illness, lack of exercise, or inadequate diet. Similarly, glycosuria may have renal as well as endocrinologic causes. Therefore, these two conditions cannot be considered diagnostic of diabetes. Gestational diabetes is diagnosed in women between the twenty-fourth and twenty-eighth weeks of gestation, first using a 50-g oral glucose load if the I-h glucose level 7.8 mmolL 140 mgdL; a 100-g oral glucose test is performed after an overnight fast. Gestational diabetes is initially treated with dietary measures; if the postprandial glucose level remains elevated, insulin therapy is often started. About 30 of women with gestational diabetes will eventually develop true diabetes mellitus. 