A 2-year-old boy is brought to clinic for a routine well-chi…
A 2-year-old boy is brought to clinic for a routine well-child visit. He is asymptomatic, but laboratory screening reveals a hemoglobin of 9.5 g/dL, mean corpuscular volume (MCV) of 68 fL (reference: 70–86 fL), and low serum ferritin. His diet consists mainly of cow’s milk and few fruits or vegetables. Physical examination is unremarkable. Which of the following is the most likely diagnosis?