title: Comparison of reticulocyte hemoglobin equivalent with traditional markers of iron and erythropoiesis in pediatric dialysis.
abstract: BACKGROUND
  Anemia is a major complication for patients on chronic dialysis. Erythropoietin is effective if iron is available, however unnecessary iron supplementation results in iron overload. Reticulocyte hemoglobin equivalent (Ret-He) may be useful for assessing iron status.
  
  
  METHODS
  A national retrospective cohort study including all children on chronic dialysis in New Zealand between 2007 and 2013, pairing Ret-He with demographic information, anemia indices, and markers of iron status.
  
  
  RESULTS
  In 606 observations, we found a modest relationship between Ret-He and transferrin saturation (TSAT) (r = 0.34, p < 0.001) and a poor correlation between Ret-He and ferritin (r = 0.09, p = 0.04). There was a negative correlation between ferritin and hemoglobin (r = -0.14, p = 0.002), a weak positive correlation between TSAT and hemoglobin (r = 0.12, p = 0.007), and a modest positive correlation between Ret-He and hemoglobin (r = 0.22, p < 0.001). The diagnostic performance of Ret-He to detect absolute iron deficiency (cut-off value 28.9 pg, sensitivity 90 %, specificity 75 %, AUC 0.87) was good.
  
  
  CONCLUSIONS
  Ret-He is a more relevant marker of iron status than ferritin and TSAT. This supports prospectively testing Ret-He to distinguish between iron deficiency and suboptimal erythropoietin dosing as competing causes for anemia. Ferritin is an unhelpful biomarker of iron deficiency in this setting.
authors.affiliation: Department of Pediatrics, Starship Children's Hospital, Auckland, New Zealand.
authors.forename: Sarka
authors.initials: S
authors.lastname: Davidkova
authors.affiliation: Blood and Cancer Centre, Starship Children's Hospital, Auckland, New Zealand.
authors.forename: Timothy D
authors.initials: TD
authors.lastname: Prestidge
authors.affiliation: Children's Research Centre, Starship Children's Hospital, Auckland, New Zealand.
authors.forename: Peter W
authors.initials: PW
authors.lastname: Reed
authors.affiliation: Department of Nephrology, Starship Children's Hospital, Park Road, Private Bag 92024, Auckland, 1142, New Zealand.
authors.forename: Tonya
authors.initials: T
authors.lastname: Kara
authors.affiliation: Department of Nephrology, Starship Children's Hospital, Park Road, Private Bag 92024, Auckland, 1142, New Zealand.
authors.forename: William
authors.initials: W
authors.lastname: Wong
authors.affiliation: Department of Nephrology, Starship Children's Hospital, Park Road, Private Bag 92024, Auckland, 1142, New Zealand. chanelp@adhb.govt.nz.
authors.forename: Chanel
authors.initials: C
authors.lastname: Prestidge
mesh_terms: D000293:Adolescent; D018798:Anemia, Iron-Deficiency / Q000097:blood / Q000175:diagnosis / Q000209:etiology*; D019540:Area Under Curve; D015415:Biomarkers / Q000097:blood; D002648:Child; D002675:Child, Preschool; D004920:Erythropoiesis; D005260:Female; D005293:Ferritins / Q000097:blood; D006304:Health Status; D006454:Hemoglobins / Q000032:analysis*; D006776:Hospitals, Pediatric; D006801:Humans; D007223:Infant; D007501:Iron / Q000097:blood*; D007676:Kidney Failure, Chronic / Q000150:complications / Q000175:diagnosis / Q000628:therapy*; D008297:Male; D009520:New Zealand; D010530:Peritoneal Dialysis / Q000009:adverse effects*; D011237:Predictive Value of Tests; D012372:ROC Curve; D006435:Renal Dialysis / Q000009:adverse effects*; D015203:Reproducibility of Results; D012156:Reticulocytes / Q000378:metabolism*; D012189:Retrospective Studies; D014168:Transferrin / Q000032:analysis
chemical_list: D015415:Biomarkers; D006454:Hemoglobins; D014168:Transferrin; D005293:Ferritins; D007501:Iron
keywords: Anemia; End-stage kidney disease; Ferritin; Iron deficiency; Reticulocyte hemoglobin equivalent; TSAT; children