You are a respiratory therapist working in a pediatrician’s…
You are a respiratory therapist working in a pediatrician’s office. You see a 16-year-old girl who presents with two chief complaints but otherwise appears to be healthy. The complaints are (1) extremely heavy menstrual bleeding and (2) severe dyspnea following relatively mild exercise. The dyspnea has been getting progressively worse over the past 3 months. Which of the following laboratory studies would you suggest to the physician in order to determine the cause of the dyspnea?