title: Influence of fasting and sample collection time on 38 biochemical markers in healthy children: a CALIPER substudy.
abstract: OBJECTIVE
  Fasting samples can be difficult to obtain in the pediatric setting, particularly in neonates. As part of the Canadian Laboratory Initiative on Pediatric Reference Intervals (CALIPER), we aimed to determine if there are differences in serum concentrations of pediatric biochemical markers measured at fasting, postprandial, and random time points throughout the day.
  
  
  METHODS
  Blood was drawn from 27 healthy children and adolescents (aged 4-18) with informed consent at 4 time points: after overnight fast, mid-morning after breakfast, within 2h after lunch, and late afternoon. The effect of fasting on 38 chemistries was evaluated by paired, two-tailed student'st-tests. Analysis of the effect of time of day was done using paired, repeated-measures ANOVA.
  
  
  RESULTS
  Fasting significantly affected 22 analytes, with HDL cholesterol being the most highly affected. Values tended to decrease postprandially, except for five analytes, including triglycerides, which increased. By ANOVA, 28 chemistries significantly differed across times of day tested.
  
  
  CONCLUSIONS
  Fasting is necessary for analysis of certain chemistries in pediatric subjects. Pediatricians should consider diurnal factors when ordering non-fasting tests and interpreting test results.
authors: Clinical Biochemistry Division, Department of Pediatric Laboratory Medicine, Hospital for Sick Children, Toronto, Ontario, Canada.
authors: M D
authors: MD
authors: Pasic
authors: D A
authors: DA
authors: Colantonio
authors: M K
authors: MK
authors: Chan
authors: A A
authors: AA
authors: Venner
authors: D
authors: D
authors: Brinc
authors: K
authors: K
authors: Adeli
mesh_terms: D000293:Adolescent; D000704:Analysis of Variance; D015415:Biomarkers / Q000097:blood; D001774:Blood Chemical Analysis / Q000592:standards*; D002648:Child; D002675:Child, Preschool; D002940:Circadian Rhythm; D005215:Fasting / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D019518:Postprandial Period; D012016:Reference Values
chemical_list: D015415:Biomarkers