title: [The application of Hoffmann method in the establishment of children's reference intervals of erythrocyte count].
abstract: OBJECTIVE
  To verify the reliability and feasibility of Hoffmann method in establishing pediatric reference intervals (RI) of erythrocyte count.
  
  
  METHODS
  Three hundreds and ninty-two thousands of hospital-based data for erythrocyte count of children aged in 1 to 17, measured by the Sysmex Xs-800i, was collected from Beijing Children's Hospital during January to December 2014. Outliers were removed using the Dixon method, then Hoffmann method was conducted to establish the gender and age stratified pediatric RIs of erythrocyte count. The erythrocyte count of 2 217 healthy children, recruited from Beijing Children's Hospital and Liaocheng Children's Hospital in Shandong province, was conducted as normal reference to verify the reliability of Hoffmann method in establishing RIs and to compare with existing RIs.
  
  
  RESULTS
  In 4 subgroups as following, male aging 1 to 12 years, male aging 13 to 17 years, female aging 1 to 12 years, female aging 13 to 17 years, the RIs of erythrocyte count established using Hoffmann method were (4.1-5.4)×10(12)/L, (4.4-5.7)×10(12)/L, (4.0-5.3)×10(12)/L, (4.0-5.3)×10(12)/L, respectively. The verification results in 2 217 healthy children showed that the proportions of out of range in four subgroups were 6.17%, 8.81%, 6.22%, 7.78%, respectively.
  
  
  CONCLUSIONS
  Hoffmann method produce reliable RIs according with the actual situation in healthy children, which is also convenient and is worth popularizing in clinical practice.
authors.affiliation: Center for Clinical Epidemiology & Evidence-based Medicine, Beijing Children's Hospital, Capital Medical University, Beijing 100045, China.
authors.forename: G S
authors.initials: GS
authors.lastname: Feng
authors.forename: W Q
authors.initials: WQ
authors.lastname: Song
authors.forename: Y J
authors.initials: YJ
authors.lastname: Lü
authors.forename: X L
authors.initials: XL
authors.lastname: Nie
authors.forename: S Y
authors.initials: SY
authors.lastname: Cai
authors.forename: T Y
authors.initials: TY
authors.lastname: Liu
authors.forename: X X
authors.initials: XX
authors.lastname: Peng
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D016208:Databases, Factual; D004906:Erythrocyte Count / Q000379:methods / Q000592:standards*; D005260:Female; D006454:Hemoglobins / Q000032:analysis / Q000592:standards; D006776:Hospitals, Pediatric; D006801:Humans; D007223:Infant; D008297:Male; D012016:Reference Values; D015203:Reproducibility of Results
chemical_list: D006454:Hemoglobins