Evaluation of NeonatalImmature Reticulocyte Fraction in Small-for-gestational Age Infant in Umbilical Cord Blood

Kang, Woong Sun; Cho, Yong Kyoon; Ko, Ji Kyung; Park, Kee Hyun; Kim, Myoung Hwan; Lee, Chul Min; Han, Tae Hee; Choi, Hoon; Kim, Bok Rin; Lee, Hong Kyoon

Abstract

OBJECTIVE
To evaluate the immature reticulocyte fraction (IRF) by automated calculator that have played a role of predicting marker for hematopoiesis induced by perinatal asphyxia.
METHODS
Hospital charts of 40 neonates with diagnosis of small for gestational age (SGA: birth weight <10 percentile) and 47 babies of appropriate for gestational age (AGA) who were delivered vaginally between May 8, 2000 and March 2, 2002 at department of Obstetric and Gynecology, Sanggye Paik Hospital, Inje university. About 5 cc in cord blood was collected immediately after delivery, the calculation of nucleated RBC (N-RBC)/100WBC by macroscopic exam and the evaluation of reticulocyte maturation by automated reticulocyte calculator (Sysmex SE 9000, TOA Medical Electronics Co., Ltd, Kobe, Japan) were performed, and made a comparative study of apgar score.
RESULTS
The comparison between AGA and SGA infants, the mean values of cord blood sampling parameter N-RBC (3.53 +/- 4.89 vs 7.92 +/- 10.06, P=0.016), middle fluorescence ratio reticulocyte (MFR) (0.21 +/- 0.02 vs 0.23 +/- 0.03, P<0.001), high fluorescence ratio reticulocyte (HFR) (0.08 +/- 0.03 vs 0.12 +/- 0.03, P<0.001), IRF (0.28 +/- 0.03 vs 0.35 +/- 0.05, P<0.001) were obtained. All of the parameters were significantly different between SGA infants and normal infants and IRF was more valuable marker than N-RBC in evaluation of hematopoietic activity in SGA infants (multiple logistic regression analysis: P value 0.282 vs <0.001).
CONCLUSION
Immature reticulocyte fraction by automated calculator is more accurate and confident marker better than N-RBC/100WBC by manual countingin evaluation of the fetal hypoxic induced hematopoiesis.