The relationship between red blood cell and reticulocyte indices and serum markers of iron status in the cord blood of newborns

Abstract

BACKGROUND: The aims of this study were to assess the relationship between red blood cell and reticulocyte indices and biochemical iron status measurements, and to define reference values of these markers in the cord blood of newborns. METHODS: In cord blood samples from 199 full-term newborns, cellular indices were assessed using an ADVIA 120 hematology system and iron status was analyzed by measurement of serum iron, transferrin, transferrin saturation (TfSat), transferrin receptor (TfR) and ferritin. RESULTS: Cellular hemoglobin in red blood cells or reticulocytes was independent of serum iron markers such as TfSat, TfR and ferritin. The percentage of hypochromic red blood cells (%HYPOm) and reticulocytes (%HYPOr) correlated significantly with TfSat and TfR-F index (TfR/log ferritin). Importantly, %HYPOm and %HYPOr were also positively correlated with the high immature reticulocyte fraction (IRF-H) and the mean cell volume of red or reticulocytes. CONCLUSIONS: In newborns, accelerated erythropoiesis is a major contributor to red blood cell and reticulocyte indices, which provide conflicting results when compared with serum markers of iron status. Apparently, the serum proteins ferritin, transferrin and TfR are more appropriate tools for the diagnosis of iron status in newborns.