title: Cell population data in neonates: differences by age group and associations with perinatal factors.
abstract: BACKGROUND
  Cell population data (CPD) describe physical parameters of white blood cell subpopulations and are reported to be of some value in the diagnosis of sepsis in neonates. Before using the CPD for diagnosing sepsis, the baseline features of the CPD distribution in healthy neonates should be clarified. The aim of this study was to compare the CPD distributions of healthy neonates and other age groups and to identify perinatal factors that are associated with changes in the CPD distribution of healthy neonates.
  
  
  METHODS
  The CPD distribution of 69 samples from term neonates was compared with adolescents and adults. The CPD distribution of 163 samples from healthy neonates was analyzed in association with perinatal factors, including gestational age, chronologic age, birthweight, delivery mode, premature rupture of membranes, diabetes, and pregnancy-induced hypertension.
  
  
  RESULTS
  The CPD distribution for term neonates was significantly different from those in adolescents and adults. The mean lymphocyte volume showed a negative correlation with gestational age at birth (r = -0.305; P < 0.01). The mean neutrophil volume was smaller in the cesarean section group than in the normal delivery group. The small for gestational age (SGA) group had smaller mean neutrophil volume and mean monocyte volume than the appropriate for gestational age group.
  
  
  CONCLUSIONS
  The CPD distribution of healthy neonates differed from those of adolescents or adults, and the differences were associated with gestational age, delivery mode, and being SGA.
authors.affiliation: Department of Pediatrics, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: J
authors.initials: J
authors.lastname: Lee
authors.affiliation: Department of Pediatrics, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: S Y
authors.initials: SY
authors.lastname: Kim
authors.affiliation: Department of Pediatrics, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: W
authors.initials: W
authors.lastname: Lee
authors.affiliation: Department of Laboratory Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: K
authors.initials: K
authors.lastname: Han
authors.affiliation: Department of Pediatrics, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: I K
authors.initials: IK
authors.lastname: Sung
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D001724:Birth Weight; D036861:Delivery, Obstetric / Q000379:methods; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007958:Leukocyte Count / Q000379:methods / Q000592:standards; D008297:Male; D011247:Pregnancy; D012307:Risk Factors; D018805:Sepsis / Q000097:blood / Q000175:diagnosis; D055815:Young Adult
keywords: Cell population data; leukocyte; neonate