Definitions
Hemoglobin (Hb) <11 g/dL was used to define anemia, according to WHO criteria.36 Participants were classified as having ID if their serum ferritin (SF) was <30 ng/mL or transferrin saturation (TS) was <16% (TS = SI/TIBC x100).37 IDA was diagnosed if there was compatibility with either laboratory criteria or therapeutic response to iron therapy.
The diagnosis of β-thal trait was based on Hb A2 level >3.5%. Infants with Hb F>10% were investigated for common beta-globin gene deletions to diagnose δβ-thal traits and hereditary persistence of fetal hemoglobin (HPFH) (Viprakasit V’s personal communication).38