Q. A 71-year-old white man visits your primary care clinic for a routine health visit. He is a veteran with an active life. He has a history of hypertension and diabetes mellitus, for which he takes medications. He also takes multivitamin tablets daily. His temperature is 98.6°F (37°C), pulse is 86 beats per minute, blood pressure is 130/70 mmHg and respiratory rate is 14 per minute. Physical examination shows pallor of the conjunctiva and mucous membranes. The rest of the examination is normal. Routine lab investigations are shown below. The peripheral blood smear shows microcytosis and hypochromic red blood cells. What is the next step in management?