Review Question - QID 214955

A 16-year-old boy presents to his primary care physician for a routine follow-up visit. He feels disappointed because his voice has not changed. He is concerned that he is not as tall as his classmates. He denies any headache, vision changes, nausea, or vomiting. He recently started playing for his high school basketball team and generally eats healthy food. He has no significant medical history and takes no medications. His temperature is 98.6°F (37.0°C), blood pressure is 115/70 mmHg, pulse is 70/min, and respirations are 12/min. On physical examination, the patient does not have facial hair or acne. His height is 60 inches and his arm span is 50 inches. His visual fields are full and he has no cranial nerve abnormalities. His strength is 5/5 in bilateral upper and lower extremities. Chest palpation and abdominal examination are unremarkable. He has no pubic hair and his testicles are symmetric with a volume of 3 mL. Which of the following is the most appropriate next step in management?