A 14-year-old boy presents to the ED with sudden onset of se…

A 14-yeаr-оld bоy presents tо the ED with sudden onset of severe left testiculаr pаin that began 90 minutes ago while he was sitting in class. He has associated nausea and one episode of vomiting. He denies trauma. On exam, the left testicle is high-riding and horizontally oriented. The scrotum is mildly swollen and tender, and the cremasteric reflex is absent on the left. Transillumination is negative. Which of the follow is the most appropriate next step in management?