Complete blood count reference intervals for extremely preterm neonates.

Area of Science:

• Neonatal Hematology
• Pediatric Clinical Chemistry

Background:

• Preterm infants have dynamic hematological profiles in early postnatal life.
• Accurate reference intervals are essential for interpreting complete blood counts (CBC) in neonates.

Purpose of the Study:

• To establish comprehensive reference intervals for CBC parameters in preterm neonates within the first five postnatal days.
• To stratify these intervals by gestational age and postnatal age.
• To compare hematological parameters between appropriate-for-gestational age (AGA) and small-for-gestational age (SGA) neonates.

Main Methods:

• Analysis of CBC data from 3128 preterm neonates (23.0-34.0 weeks gestation) admitted to a neonatal intensive care unit.
• Generation of percentile-based reference intervals (2.5th, 10th, 50th, 90th, 97.5th) for leukocytes, thrombocytes, hemoglobin, hematocrit, neutrophilic granulocytes, and lymphocytes.
• Application of stringent exclusion criteria and comparison between AGA and SGA neonates.

Main Results:

• Reference intervals were established for key hematological parameters across different gestational and postnatal ages.
• Significant differences were observed between AGA and SGA neonates, with SGA infants showing lower leukocytes, thrombocytes, and neutrophilic granulocytes.
• Hemoglobin and hematocrit levels were generally similar between AGA and SGA groups, with minor variations at specific gestational ages.

Conclusions:

• The study provides validated reference intervals for neonatal hematology, improving clinical interpretation of CBC results in preterm infants.
• The established intervals facilitate the identification of hematological deviations.
• Observed differences between AGA and SGA neonates highlight the impact of fetal growth restriction on neonatal hematopoiesis, warranting further investigation.