Which of the following is a characteristic of type 1 diabetes mellitus?

Type 1 diabetes mellitus is characterized by the autoimmune destruction of pancreatic beta cells, which leads to an absolute deficiency of insulin. This deficiency is significant because insulin is essential for glucose uptake by tissues and for regulating glucose metabolism. Without adequate insulin, the body cannot utilize glucose effectively, leading to increased blood glucose levels and the risk of diabetic ketoacidosis (DKA), a serious condition that occurs when the body starts breaking down fats at an excessive rate, producing ketones and resulting in acidosis.

To manage type 1 diabetes and prevent ketosis and related complications, individuals require insulin replacement therapy. This is crucial for regulating blood glucose levels, promoting glucose uptake into cells, and preventing the body from entering a state of ketosis. Thus, requiring insulin replacement is a definitive characteristic of type 1 diabetes mellitus.

While the other options mention various aspects of diabetes tests and classifications, they do not accurately represent the defining features and management requirements of type 1 diabetes, which is fundamentally reliant on insulin therapy for survival and maintenance of metabolic health.