A review of cord blood concentrations of iron status parameters to define reference ranges for preterm infants.

BACKGROUND Iron plays an essential role in various tissue functions, and hence the reliable assessment of iron nutrition status of preterm infants appears to be mandatory. OBJECTIVES To summarize available data on cord blood concentrations of iron status parameters as surrogate reference ranges for preterm infants until term-equivalent age. METHODS Review of the literature searching PubMed for cord blood values of hemoglobin, mean corpuscular volume, ferritin, soluble transferrin receptor, ferritin index, transferrin saturation, reticulocyte hemoglobin content, zinc protoporphyrin/heme ratio, and hepcidin and comparison with reference ranges established for adults. RESULTS Gestational age-specific cord blood concentration ranges at term were computed as weighted mean for hemoglobin [15.9 g/dl (13.3-18.4)], mean corpuscular volume [108.1 fl (97.8-118.5)] and transferrin saturation [61.2% (31.5-90.9)] and listed for ferritin, soluble transferrin receptor, ferritin index, zinc protoporphyrin/heme ratio, reticulocyte hemoglobin content and hepcidin. These surrogate reference ranges were markedly different from adult values. CONCLUSION Reference ranges of iron status parameters established for adults are probably not suitable to define iron status in preterm infants. If iron supplementation in preterm infants should be individually adjusted based on iron status parameters, it may be necessary to aim for cord blood concentration ranges to enable optimal growth and development.