title: Age- and sex-specific dynamics in 22 hematologic and biochemical analytes from birth to adolescence.
abstract: BACKGROUND
  Pediatric laboratory test results must be interpreted in the context of interindividual variation and age- and sex-dependent dynamics. Reference intervals as presently defined for separate age groups can only approximate the age-related dynamics encountered in pediatrics. Continuous reference intervals from birth to adulthood are not available for most laboratory analytes because of the ethical and practical constraints of defining reference intervals using a population of healthy community children. We applied an indirect method to generate continuous reference intervals for 22 hematologic and biochemical analytes by analyzing clinical laboratory data from blood samples taken during clinical care of patients.
  
  
  METHODS
  We included samples from 32 000 different inpatients and outpatients (167 000 samples per analyte) from a German pediatric tertiary care center. Measurements were performed on a Sysmex-XE 2100 and a Cobas Integra 800 during clinical care over a 6-year period. The distribution of samples considered normal was estimated with an established indirect statistical approach and used for the calculation of reference intervals.
  
  
  RESULTS
  We provide continuous reference intervals from birth to adulthood for 9 hematology analytes (hemoglobin, hematocrit, red cell indices, red cell count, red cell distribution width, white cell count, and platelet count) and 13 biochemical analytes (sodium, chloride, potassium, calcium, magnesium, phosphate, creatinine, aspartate transaminase, alanine transaminase, γ-glutamyltransferase, alkaline phosphatase, lactate dehydrogenase, and total protein).
  
  
  CONCLUSIONS
  Continuous reference intervals capture the population changes in laboratory analytes during pediatric development more accurately than age groups. After local validation, the reference intervals provided should allow a more precise consideration of these dynamics in clinical decision making.
authors.affiliation: Department of Pediatrics and Adolescent Medicine, University Hospital Erlangen, Erlangen, Germany;
authors.forename: Jakob
authors.initials: J
authors.lastname: Zierk
authors.affiliation: Department of Statistics, University of Bremen, Bremen, Germany;
authors.forename: Farhad
authors.initials: F
authors.lastname: Arzideh
authors.affiliation: Department of Pediatrics and Adolescent Medicine, University Hospital Erlangen, Erlangen, Germany;
authors.forename: Tobias
authors.initials: T
authors.lastname: Rechenauer
authors.affiliation: Bremer Zentrum für Laboratoriumsmedizin, Klinikum Bremen Mitte, Bremen, Germany.
authors.forename: Rainer
authors.initials: R
authors.lastname: Haeckel
authors.affiliation: Department of Pediatrics and Adolescent Medicine, University Hospital Erlangen, Erlangen, Germany;
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Rascher
authors.affiliation: Department of Pediatrics and Adolescent Medicine, University Hospital Erlangen, Erlangen, Germany;
authors.forename: Markus
authors.initials: M
authors.lastname: Metzler
authors.affiliation: Department of Pediatrics and Adolescent Medicine, University Hospital Erlangen, Erlangen, Germany; manfred.rauh@uk-erlangen.de.
authors.forename: Manfred
authors.initials: M
authors.lastname: Rauh
mesh_terms: D000293:Adolescent; D000410:Alanine Transaminase / Q000097:blood; D000469:Alkaline Phosphatase / Q000097:blood; D001219:Aspartate Aminotransferases / Q000097:blood; D001774:Blood Chemical Analysis / Q000379:methods; D002648:Child; D002675:Child, Preschool; D003404:Creatinine / Q000097:blood; D005260:Female; D006400:Hematocrit; D006403:Hematologic Tests / Q000379:methods; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D007223:Infant; D007770:L-Lactate Dehydrogenase / Q000097:blood; D007958:Leukocyte Count; D008297:Male; D010976:Platelet Count; D012016:Reference Values
chemical_list: D006454:Hemoglobins; D003404:Creatinine; D007770:L-Lactate Dehydrogenase; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase; D000469:Alkaline Phosphatase