A 12-year-old black boy undergoes his annual physical examination. He has no symptoms, does not participate in any sports, and has a sedentary lifestyle, but he performs well at school. His mother and both maternal grandparents have a history of Type 2 diabetes.

His body mass index is 27.6, which is more than the 95th percentile for age and sex. His blood pressure is 110/72 mm Hg. Dark, velvety pigmentation is noted over the back of his neck. The remainder of his physical examination shows no abnormalities.

QUESTION:

In addition to diet and exercise counseling, which of the following is the most appropriate next step in the evaluation of this patient?

A. Measure fasting blood glucose.

B. Measure islet cell antibodies.

C. Measure 24-hour urinary cortisol. 

D. Perform a 2-hour oral glucose tolerance test. 

E. Screen the patient for diabetes when he is age 16 years