title: Peripheral leukocyte count and leukocyte indexes in healthy newborn term infants.
abstract: OBJECTIVE
  This study was designed to determine normal values for the peripheral leukocyte count and leukocyte indexes in healthy term neonates at a specific time after birth.
  
  
  METHODS
  We prospectively enrolled 193 healthy term-gestation neonates with no identifiable perinatal risk factors for sepsis. At 4 hours of age a blood sample was collected by warmed heel stick. An automated Coulter complete blood cell count and a 100-cell manual differential leukocyte count were performed on each sample. The differential count was performed by a single hematopathologist unaware of the clinical status of each infant. Perinatal factors were identified by review of the mothers' and infants' hospital records.
  
  
  RESULTS
  The mean ratio of immature to total neutrophils was 0.16 (SD 0.10), and the 10% to 90% range was 0.05 to 0.27. The mean leukocyte count was 24.06 x 10(9)/L (24,060/mm3), and the 10% to 90% range was 16.2 to 31.5 x 10(9)/L (16,200 to 31,500/mm3). Neutropenia, < 1.5 x 10(9)/L (1500/mm3) segmented plus band form neutrophils, was not observed. Of all the perinatal factors studied, only the duration of stage 1 labor was found to be associated with significant elevations in the leukocyte and absolute neutrophil counts.
  
  
  CONCLUSIONS
  Previously published normal ranges for leukocyte indexes in healthy newborn infants during the early neonatal period are too restrictive; reference standards should be broadened.
authors.affiliation: Department of Pediatrics, Wilford Hall United States Air Force Medical Center, Lackland Air Force Base, Texas.
authors.forename: R L
authors.initials: RL
authors.lastname: Schelonka
authors.forename: B A
authors.initials: BA
authors.lastname: Yoder
authors.forename: S E
authors.initials: SE
authors.lastname: desJardins
authors.forename: R B
authors.initials: RB
authors.lastname: Hall
authors.forename: J
authors.initials: J
authors.lastname: Butler
mesh_terms: D001772:Blood Cell Count; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn / Q000097:blood / Q000276:immunology*; D007958:Leukocyte Count; D009504:Neutrophils; D012016:Reference Values