title: Serum eosinophil cationic protein (ECP): reference values in healthy nonatopic children.
abstract: BACKGROUND
  Although serum ECP concentrations have been reported in normal children, there are currently no published upper cutoff reference limits for serum ECP in normal, nonatopic, nonasthmatic children aged 1-15 years.
  
  
  METHODS
  We recruited 123 nonatopic, nonasthmatic normal children attending the Royal Belfast Hospital for Sick Children for elective surgery and measured serum ECP concentrations. The effects of age and exposure to environmental tobacco smoke (ETS) on the upper reference limits were studied by multiple regression and fractional polynomials.
  
  
  RESULTS
  The median serum ECP concentration was 6.5 microg/l and the 95th and 97.5 th percentiles were 18.8 and 19.9 microg/l. The median and 95th percentile did not vary with age. Exposure to ETS was not associated with altered serum ECP concentrations (P = 0.14).
  
  
  CONCLUSIONS
  The 95th and 97.5 th percentiles for serum ECP for normal, nonatopic, nonasthmatic children (aged 1-15 years) were 19 and 20 microg/l, respectively. Age and exposure to parental ETS did not significantly alter serum ECP concentrations or the normal upper reference limits. Our data provide cutoff upper reference limits for normal children for use of serum ECP in a clinical or research setting.
authors.affiliation: Department of Clinical Biochemistry, The Queen's University of Belfast, UK.
authors.forename: P S
authors.initials: PS
authors.lastname: Fitch
authors.forename: V
authors.initials: V
authors.lastname: Brown
authors.forename: B C
authors.initials: BC
authors.lastname: Schock
authors.forename: R
authors.initials: R
authors.lastname: Taylor
authors.forename: M
authors.initials: M
authors.lastname: Ennis
authors.forename: M D
authors.initials: MD
authors.lastname: Shields
mesh_terms: D000293:Adolescent; D000367:Age Factors; D001798:Blood Proteins / Q000032:analysis*; D002648:Child; D002675:Child, Preschool; D047091:Eosinophil Granule Proteins; D004804:Eosinophils / Q000737:chemistry*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D012016:Reference Values; D012044:Regression Analysis; D012260:Ribonucleases; D012737:Sex Factors
chemical_list: D001798:Blood Proteins; D047091:Eosinophil Granule Proteins; D012260:Ribonucleases