title: Usefulness of serum transferrin receptor and serum ferritin in diagnosis of iron deficiency in infancy.
abstract: BACKGROUND
  The serum transferrin receptor (TfR) and the ratio of TfR to serum ferritin (TfR:SF) have been shown to be useful as early indicators of iron deficiency.
  
  
  OBJECTIVE
  The objective of this study was to evaluate the performance of TfR and TfR:SF in the assessment of iron deficiency in infants and to analyze age-related changes in both variables.
  
  
  METHODS
  A total of 716 blood samples obtained from 515 healthy infants aged 8-15 mo were studied.
  
  
  RESULTS
  In 144 samples in which all other laboratory indicators of iron status were within the reference range, the median and 95% CI for TfR and TfR:SF were 8.5 mg/L (95% CI: 5.9, 13.5) and 497 (95% CI: 134, 975), respectively. TfR and TfR:SF were significantly correlated with the other laboratory indicators of iron status. Furthermore, as the severity of iron deficiency progressed, there was a gradual increase in mean TfR concentration (P: < 0.00001; analysis of variance). The sensitivity of TfR > 13.5 mg/L and TfR:SF > 975 in the diagnosis of iron deficiency was 23.6% and 68.4%, respectively. The specificity was 98.3% and 63.3% for TfR and TfR:SF, respectively. The sensitivity and specificity of SF < 10 microg/L were 63.7% and 60.8%, respectively. Receiver operator characteristic analysis showed that TfR and TfR:SF were more accurate than was SF alone in the diagnosis of iron deficiency.
  
  
  CONCLUSIONS
  TfR and TfR:SF showed age-related changes; TfR and TfR:SF appear to be better diagnostic tests for iron deficiency in infants than SF.
authors.affiliation: Institute of Nutrition and Food Technology, University of Chile, Santiago, Chile. molivare@uec.inta.uchile.cl
authors.forename: M
authors.initials: M
authors.lastname: Olivares
authors.forename: T
authors.initials: T
authors.lastname: Walter
authors.forename: J D
authors.initials: JD
authors.lastname: Cook
authors.forename: E
authors.initials: E
authors.lastname: Hertrampf
authors.forename: F
authors.initials: F
authors.lastname: Pizarro
mesh_terms: D000375:Aging; D004906:Erythrocyte Count; D004909:Erythrocyte Indices; D005260:Female; D005293:Ferritins / Q000097:blood*; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D007223:Infant; D000090463:Iron Deficiencies; D008297:Male; D012372:ROC Curve; D011990:Receptors, Transferrin / Q000097:blood*; D012016:Reference Values; D012680:Sensitivity and Specificity
chemical_list: D006454:Hemoglobins; D011990:Receptors, Transferrin; D005293:Ferritins