title: Establishing age/sex related serum creatinine reference intervals from hospital laboratory data based on different statistical methods.
abstract: BACKGROUND
  This is a retrospective study on a large hospital database to establish age- and sex-related mean values and reference ranges for serum creatinine (Scr), obtained with an IDMS-traceable, enzymatic method, in a Caucasian population.
  
  
  METHODS
  The database was filtered for unique entries to reduce the presence of correlated and pathological data. Three different statistical methods, a non-parametric method, the Bhattacharya procedure and a non-linear fit of the cumulative Gaussian distribution were used to estimate the serum creatinine-age dependency for men and women, from birth till 100 years of age.
  
  
  RESULTS
  Scr increases with age, equal for boys and girls, up to 14 years and with a much steeper slope for boys than for girls between 14 and 20 years. We show that the Scr-age pattern is constant between 20 and 70 years with a mean of 0.90 mg/dL [0.63-1.16 mg/dL] for men and 0.70 mg/dL [0.48-0.93 mg/dL] for women. Above 70, Scr starts to slowly increase again.
  
  
  CONCLUSIONS
  Indirect methods confirm the available reference intervals from healthy-volunteer studies and add information on age-periods not covered by these studies. As such, indirect methods can be used complementary to healthy-volunteer studies.
authors.affiliation: Interdisciplinary Research Center, Katholieke Universiteit Leuven Campus Kortrijk, Department of Clinical Chemistry, AZ Groeninge Hospital, Kortrijk, Belgium. hans.pottel@kuleuven-kortrijk.be
authors.forename: Hans
authors.initials: H
authors.lastname: Pottel
authors.forename: Nicolas
authors.initials: N
authors.lastname: Vrydags
authors.forename: Boris
authors.initials: B
authors.lastname: Mahieu
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Vandewynckele
authors.forename: Kathleen
authors.initials: K
authors.lastname: Croes
authors.forename: Frank
authors.initials: F
authors.lastname: Martens
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D003404:Creatinine / Q000097:blood*; D005260:Female; D006761:Hospitals; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D013677:Medical Laboratory Science / Q000379:methods*; D008875:Middle Aged; D012727:Sex Characteristics
chemical_list: D003404:Creatinine