title: The diagnostic criteria for iron deficiency in infants should be reevaluated.
abstract: Diagnostic criteria for iron deficiency (ID) and iron deficiency anemia (IDA) in infants are poorly defined. Our aim was to establish appropriate cut-off values for hemoglobin (Hb), plasma ferritin, erythrocyte mean cell volume (MCV), zinc protoporphyrin (ZPP) and soluble transferrin receptors (TfR) in infancy. Exclusively breast-fed infants (n = 263) in Honduras and Sweden were randomly assigned to receive iron supplementation or placebo, and blood samples were obtained at 4, 6 and 9 mo of age. Reference ranges were determined using three different approaches for defining iron-replete infants. The usefulness of several variables for predicting the Hb response to iron was evaluated. We found the following 2 SD cut-off values in iron-replete infants: Hb <105 g/L at 4-6 mo and <100 g/L at 9 mo; ZPP >75 micro mol/mol heme at 4-6 mo and >90 micro mol/mol heme at 9 mo; ferritin <20 micro g/L at 4 mo, <9 micro g/L at 6 mo and <5 micro g/L at 9 mo; and TfR >11 mg/L at 4-9 mo. The Hb response to iron was not a useful definition of IDA at 4 mo of age. Hb, MCV and ZPP at 6 mo as well as growth variables predicted the Hb response at 6-9 mo, but ferritin and TfR at 6 mo did not. We conclude that there is need for a reevaluation of the definitions of ID and IDA in infants.
authors.affiliation: Department of Clinical Sciences, Pediatrics, Umeå University, Sweden. magnus.domellof@pediatri.umu.se
authors.forename: Magnus
authors.initials: M
authors.lastname: Domellöf
authors.forename: Kathryn G
authors.initials: KG
authors.lastname: Dewey
authors.forename: Bo
authors.initials: B
authors.lastname: Lönnerdal
authors.forename: Roberta J
authors.initials: RJ
authors.lastname: Cohen
authors.forename: Olle
authors.initials: O
authors.lastname: Hernell
mesh_terms: D018798:Anemia, Iron-Deficiency / Q000097:blood / Q000175:diagnosis*; D004909:Erythrocyte Indices; D005293:Ferritins / Q000032:analysis; D017408:Guidelines as Topic; D006454:Hemoglobins / Q000032:analysis / Q000592:standards; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007232:Infant, Newborn, Diseases / Q000097:blood / Q000175:diagnosis*; D007501:Iron / Q000008:administration & dosage; D011524:Protoporphyrins / Q000097:blood; D011990:Receptors, Transferrin / Q000097:blood; D012016:Reference Values
chemical_list: D006454:Hemoglobins; D011524:Protoporphyrins; D011990:Receptors, Transferrin; C017803:zinc protoporphyrin; D005293:Ferritins; D007501:Iron