IN THE not-too-distant past, it was taught that the 3 most common causes of hypochromic microcytic anemia in childhood were all forms of iron deficiency. Although this may still be true, in actual practice there are a number of confounding variables (eg, a declining prevalence of iron deficiency anemia [IDA] in the United States, imperfect screening tests that rarely include red blood cell indices, and confusion about what hemoglobin [Hb] level should be used to identify anemia, especially in black infants).
Abelson HT. Complexities in Recognizing and Treating Iron Deficiency Anemia. Arch Pediatr Adolesc Med. 2001;155(3):332-333. doi:10.1001/archpedi.155.3.332