title: Pediatric reference intervals for lymphocyte vitamin C (ascorbic acid).
abstract: OBJECTIVE
  To establish pediatric reference intervals for lymphocyte vitamin C.
  
  
  METHODS
  This was a prospective study of 194 well children aged 0-7 years old of mixed ethnicity who had blood drawn for the purpose of this study. Blood was collected during elective surgery under general anesthesia and lymphocytes isolated and stored as frozen ascorbic acid lymphocyte lysates for later HPLC analysis by previously described methodology. Reference intervals were established according to the Clinical and Laboratory Standards Institute (CLSI) and the International Federation of Clinical Chemistry (IFCC) guidelines (C28-A3). Horn-Pesce robust method was used to estimate the 95% confidence interval and 95% reference interval.
  
  
  RESULTS
  Reference intervals were independent of age or gender and shown to be 12.9-52.8 μg/10(8) cells (lymphocytes).
  
  
  CONCLUSIONS
  We have defined pediatric reference ranges for lymphocyte vitamin C in healthy, fasted children at a relevant age group (0-7 years). The new reference interval can now be used to more reliably explore possible implications of variation of vitamin C levels on bleeding and other clinical signs.
authors.affiliation: Pediatric Ophthalmology and Ocular Genetics, Wills Eye Institute, Philadelphia, PA, USA.
authors.forename: Alex
authors.initials: A
authors.lastname: Levin
authors.forename: Charmaine
authors.initials: C
authors.lastname: DeSouza
authors.forename: Christian
authors.initials: C
authors.lastname: Zaarour
authors.forename: Warren
authors.initials: W
authors.lastname: Walsh
authors.forename: Man Khun
authors.initials: MK
authors.lastname: Chan
authors.forename: Zulfikarali
authors.initials: Z
authors.lastname: Verjee
authors.forename: Susan
authors.initials: S
authors.lastname: McIntyre
authors.forename: Khosrow
authors.initials: K
authors.lastname: Adeli
mesh_terms: D001205:Ascorbic Acid / Q000032:analysis*; D002624:Chemistry, Clinical / Q000592:standards*; D002648:Child; D002675:Child, Preschool; D002851:Chromatography, High Pressure Liquid / Q000379:methods / Q000592:standards*; D005006:Ethnicity; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008214:Lymphocytes / Q000737:chemistry*; D011446:Prospective Studies; D012016:Reference Values; D011795:Surveys and Questionnaires
chemical_list: D001205:Ascorbic Acid