title: Soluble transferrin receptor in Aboriginal children with a high prevalence of iron deficiency and infection.
abstract: OBJECTIVE
  Aboriginal children in tropical Australia have a high prevalence of both iron deficiency and acute infections, making it difficult to differentiate their relative contributions to anaemia. The aims of this study were to compare soluble transferrin receptor with ferritin in iron deficiency anaemia (IDA), and to examine how best to distinguish the effect of iron deficiency from infection on anaemia.
  
  
  METHODS
  We conducted a prospective study of 228 admissions to Royal Darwin Hospital in children from 6 to 60 months of age. Transferrin receptor concentrations were measured by a particle-enhanced immunoturbidimetric assay and ferritin by a microparticle enzyme immunoassay.
  
  
  RESULTS
  On multiple regression, the best explanatory variables for haemoglobin differences (r2=33.7%, P<0.001) were mean corpuscular volume (MCV), red cell distribution width (RDW) and C-reactive protein (CRP); whereas transferrin receptor and ferritin were not significant (P>0.4). Using > or =2 abnormal indices (MCV, RDW, blood film)+haemoglobin <110 g/l as the reference standard for IDA, transferrin receptor produced a higher area under the curve on receiver operating characteristic curve analysis than ferritin (0.79 vs. 0.64, P<0.001) or the transferrin receptor-ferritin index (0.77). On logistic regression, the effect of acute infection (CRP) on haemoglobin was significant (P<0.001) at cut-offs of 105 and 110 g/l, but not at 100 g/l when only iron deficiency indicators (MCV, RDW, blood film) were significant.
  
  
  CONCLUSIONS
  Transferrin receptor does not significantly improve the diagnosis of anaemia (iron deficiency vs. infection) over full blood count and CRP, but in settings with a high burden of infectious diseases and iron deficiency, it is a more reliable adjunctive measure of iron status than ferritin.
authors.affiliation: Northern Territory Clinical School, Casuarina, Australia.
authors.forename: B
authors.initials: B
authors.lastname: Ritchie
authors.forename: Y
authors.initials: Y
authors.lastname: McNeil
authors.forename: D R
authors.initials: DR
authors.lastname: Brewster
mesh_terms: D018798:Anemia, Iron-Deficiency / Q000097:blood* / Q000453:epidemiology; D019540:Area Under Curve; D001315:Australia / Q000453:epidemiology; D015415:Biomarkers / Q000097:blood*; D002097:C-Reactive Protein / Q000032:analysis; D002675:Child, Preschool; D004909:Erythrocyte Indices; D005260:Female; D005293:Ferritins / Q000097:blood; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D008297:Male; D015995:Prevalence; D011446:Prospective Studies; D011990:Receptors, Transferrin / Q000097:blood*; D012044:Regression Analysis
chemical_list: D015415:Biomarkers; D006454:Hemoglobins; D011990:Receptors, Transferrin; D002097:C-Reactive Protein; D005293:Ferritins