title: Zinc protoporphyrin/heme as an indicator of iron status in NICU patients.
abstract: OBJECTIVE
  Zinc protoporphyrin/heme ratio (ZnPP/H) has been well established as an indicator of functional iron deficiency in subjects 6 months of age to adult. The primary objective of this study was to establish normative values for ZnPP/H in NICU patients and secondarily to explore the utility of this test as an indicator of iron deficiency in neonates. Study design ZnPP/H and complete blood counts were obtained weekly on consecutive NICU patients. Gestational age, growth variables, iron supplementation, erythropoietin treatment, and blood transfusions were documented. Results are reported as mean +/- SD. A value of P <.05 was considered significant.
  
  
  RESULTS
  ZnPP/H ratios (n = 639) were evaluated from 143 infants. During the first week of life, ZnPP/H was inversely correlated with gestational age (n = 78, P <.001, r = -0.72). Maternal diabetes, growth retardation, and exposure to chorioamnionitis were independent risk factors for high ZnPP/H. Both iron supplementation and blood transfusion decreased ZnPP/H (P <.001). Erythropoietin treatment was associated with an increase in reticulocyte count and ZnPP/H (P <.001).
  
  
  CONCLUSIONS
  ZnPP/H is inversely correlated with gestational age, and the range in all newborn infants is higher than in adults. ZnPP/H is elevated in certain infant subpopulations, which suggests that they may require additional iron supplementation.
authors.affiliation: Department of Pediatrics, University of Washington, Seattle, Washington 98195, USA. sjuul@u.washington.edu
authors.forename: Sandra E
authors.initials: SE
authors.lastname: Juul
authors.forename: Joan C
authors.initials: JC
authors.lastname: Zerzan
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Strandjord
authors.forename: David E
authors.initials: DE
authors.lastname: Woodrum
mesh_terms: D015415:Biomarkers / Q000097:blood; D001772:Blood Cell Count; D017707:Erythrocyte Transfusion; D004921:Erythropoietin / Q000627:therapeutic use; D005296:Ferrous Compounds / Q000627:therapeutic use; D005865:Gestational Age; D006418:Heme / Q000032:analysis*; D006801:Humans; D007231:Infant, Newborn; D007363:Intensive Care Units, Neonatal; D000090463:Iron Deficiencies; D011524:Protoporphyrins / Q000097:blood*; D011994:Recombinant Proteins; D012016:Reference Values; D012307:Risk Factors
chemical_list: D015415:Biomarkers; D005296:Ferrous Compounds; D011524:Protoporphyrins; D011994:Recombinant Proteins; D004921:Erythropoietin; C017803:zinc protoporphyrin; C020748:ferrous sulfate; D006418:Heme