Zinc protoporphyrin/heme as an indicator of iron status in NICU patients.
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.
Juul
Sandra E
SE
Department of Pediatrics, University of Washington, Seattle, Washington 98195, USA. sjuul@u.washington.edu
Zerzan
Joan C
JC
Strandjord
Thomas P
TP
Woodrum
David E
DE
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
D015415:Biomarkers; D005296:Ferrous Compounds; D011524:Protoporphyrins; D011994:Recombinant Proteins; D004921:Erythropoietin; C017803:zinc protoporphyrin; C020748:ferrous sulfate; D006418:Heme