title: Reference intervals for reticulocyte parameters of infants during their first 90 days after birth.
abstract: OBJECTIVE
  The automated reticulocyte parameters (absolute reticulocyte count, immature reticulocyte fraction (IRF) and reticulocyte hemoglobin content (RET-He)) are of value in managing adults and older children with a variety of hematological disorders. However, the lack of reference intervals for these parameters in neonates and young infants has limited their application to that population.
  
  
  METHODS
  During a span of 12 months (29 May 2014 to 5 May 2015), a convenience sample of reticulocyte parameters were run from clinically ordered complete blood counts (CBCs) of infants within the first 90 days after birth. Measuring the reticulocyte parameters as a research-only adjunct to the CBC did not require any additional blood or generate a patient charge, and the reticulocyte results were not reported to the provided and did not appear in the clinical records. Values from neonates who had a transfusion or a diagnosis of anemia were subsequently excluded from the reference data set.
  
  
  RESULTS
  Nine Intermountain Healthcare clinical laboratories contributed 8438 CBCs to the initial reticulocyte parameter database. From these, 1806 were excluded because of a transfusion or a diagnosis of anemia, leaving 6632 in the reference interval database. The parameters charted over the first 90 days after birth were: (1) blood hemoglobin concentration (g dl(-1)), (2) mean corpuscular volume (fL), (3) reticulocyte count (x10(3) per μl), (4) IRF (%) and (5) RET-He (pg).
  
  
  CONCLUSIONS
  The new reference interval charts can help clinicians identify abnormalities in the reticulocyte parameters. This information could be of value in identifying and following neonates with various hematological problems including hemolytic disorders, occult hemorrhage, or iron deficiency or other limitations of erythrocyte production.
authors.affiliation: Division of Neonatology, Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, UT, USA.|Women and Newborn's Program, Intermountain Healthcare, Salt Lake City, UT, USA.|Division of Hematology/Oncology, Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, UT, USA.
authors.forename: R D
authors.initials: RD
authors.lastname: Christensen
authors.affiliation: Women and Newborn's Program, Intermountain Healthcare, Salt Lake City, UT, USA.|Institute for Healthcare Delivery Research, Salt Lake City, UT, USA.
authors.forename: E
authors.initials: E
authors.lastname: Henry
authors.affiliation: Department of Pathology, Intermountain Medical Center, Murray, UT, USA.
authors.forename: S T
authors.initials: ST
authors.lastname: Bennett
authors.affiliation: Division of Hematology/Oncology, Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, UT, USA.
authors.forename: H M
authors.initials: HM
authors.lastname: Yaish
mesh_terms: D016208:Databases, Factual; D004909:Erythrocyte Indices; D005260:Female; D006454:Hemoglobins / Q000032:analysis*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D012016:Reference Values; D017701:Reticulocyte Count; D012156:Reticulocytes / Q000166:cytology*; D014481:United States
chemical_list: D006454:Hemoglobins