A 67-year-old man presents with anemia and fatigue. He does not drink alcohol
and denies any significant occupational exposures to chemicals. His MCV is 105 fl.
His folate level is normal. His vitamin B12 level is 292 pg/mL. Methylmalonic acid
and homocysteine levels are normal. A peripheral blood smear is shown in Figure
51Q-1. What is the most likely cause of this man’s anemia?
A. Myelodysplastic syndrome
B. Folate deficiency
C. Vitamin B12 deficiency
D. Beta-thalassemia trait
