Q. A 28-year-old woman has been referred by her physician to the hematology clinic with a history of recurrent episodes of dark urine, fatigue, and abdominal pain for the past year. She reports that these symptoms seem to worsen in the morning and gradually improve throughout the day. She is not on any medication. 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 scleral icterus is noted. The rest of the examination is unremarkable. Laboratory results are shown below. The peripheral blood smear shows a normocytic normochromic blood picture. What is the most appropriate next step in her management?