title: Serum transferrin receptor in children: usefulness for determinating the nature of anemia in infection.
abstract: OBJECTIVE
  To know the variations of serum transferrin receptor (sTfR) and its indices depending on the status of body iron and the presence of infection in children, to evaluate their usefulness for recognizing the nature of anemia in infection, and to know the role of erythropoietic activity in these conditions.
  
  
  METHODS
  Three hundred and sixty-eight children between 1 and 10 years were included: 206 healthy children; 60 iron deficient anemic children (IDA); 102 with anemia and infectious disease, 58 of them meeting criteria for IDA. We measured hemoglobin, red cell indices, reticulocytes, transferrin saturation, serum ferritin, erythrocyte protoporphyrin, serum erythropoietin, and sTfR. Statistic method: ANOVA test, multiple linear regression, and ROC curve.
  
  
  RESULTS
  sTfR, sTfR/ferritin ratio, and sTfR-logferritin index values were found to increase significantly in IDA children. These values were significantly lower in infectious anemia than iron deficiency states. Serum erythropoietin only was elevated significantly in iron deficiency states. In children without infection, mean corpuscular hemoglobin, erythrocyte protoporphirin, erythropoietin logarithm, and total-iron-binding-capacity logarithm predicted 81% of sTfR variability. sTfR and its indices showed a very high sensitivity and specificity for recognizing iron deficiency states. In children with IDA and infection sensitivity for sTfR/ferritin ratio was low (area under the curve: 0.71; 95% confidence interval: 0.64-0.88). For discriminating the nature of anemia in infection the cut-off point obtained for sTfR, sTfR/ferritin ratio, and sTfR-F index were 3, 70, and 1.8, respectively, and their sensitivity and specificity were also very high.
  
  
  CONCLUSIONS
  sTfR, sTfR/ferritin ratio, and sTfR-F index are useful parameters for recognizing iron deficiency and the nature of anemia in infection. In IDA+infection, sTfR/ferritin ratio should not be recommended in the diagnosis of iron deficiency. In iron deficiency, erythropoietic activity has a secondary role as predictor factor of sTfR levels.
authors.affiliation: Departments of Pediatrics, Hospital Torrecárdenas, Almería, Spain. mavazquezl@cajamar.es
authors.forename: M
authors.initials: M
authors.lastname: Angeles Vázquez López
authors.forename: Francisco Lendinez
authors.initials: FL
authors.lastname: Molinos
authors.forename: Moisés Leyva
authors.initials: ML
authors.lastname: Carmona
authors.forename: Amparo Carracedo
authors.initials: AC
authors.lastname: Morales
authors.forename: Francisco Javier
authors.initials: FJ
authors.lastname: Muñoz Vico
authors.forename: Juan López
authors.initials: JL
authors.lastname: Muñoz
authors.forename: Antonio
authors.initials: A
authors.lastname: Muñoz Hoyos
mesh_terms: D018798:Anemia, Iron-Deficiency / Q000097:blood* / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology; D015415:Biomarkers / Q000097:blood; D002648:Child; D002675:Child, Preschool; D004920:Erythropoiesis; D004921:Erythropoietin / Q000097:blood; D005260:Female; D005293:Ferritins / Q000097:blood; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D007223:Infant; D007239:Infections / Q000097:blood* / Q000150:complications / Q000453:epidemiology; D008297:Male; D011524:Protoporphyrins / Q000097:blood; D011990:Receptors, Transferrin / Q000097:blood*; D017701:Reticulocyte Count; D014168:Transferrin / Q000032:analysis
chemical_list: D015415:Biomarkers; D006454:Hemoglobins; D011524:Protoporphyrins; D011990:Receptors, Transferrin; D014168:Transferrin; D004921:Erythropoietin; D005293:Ferritins