Q. A 32-year-old previously healthy woman comes to her physician’s office complaining of increasing fatigue, pallor, and shortness of breath over the past few months. She reports no significant medical history and is not taking any medications. Her menstrual history is regular with a scanty flow of blood. Her temperature is 98.4°F (36.8°C), heart rate is 80/min, respiratory rate is 14/minute, and blood pressure is 110/70 mm of Hg. On physical examination, she appears pale, and conjunctival pallor is evident. The rest of the examination is unremarkable. Laboratory results are shown below. The peripheral blood smear shows normocytic and normochromic red blood cells with no evidence of hemolysis or spherocytosis. What is the most appropriate next step in her management?