title: Methodological considerations with the use of urine samples for assessment of mercury excretion and markers of renal damage.
abstract: OBJECTIVE
  To provide recommendations for design and analysis of studies using urine specimens to evaluate renal function or mercury excretion in children.
  
  
  METHODS
  An analysis of mercury, albumin, γ-glutamyl transpeptidase (γ-GT) and N-acetyl-β-D-glucosaminidase (NAG) concentrations was carried out.
  
  
  RESULTS
  Mercury concentration and creatinine-corrected renal markers were higher in daytime compared with overnight samples. Excretion rates increased with urinary flow rate. γ-GT and NAG concentrations decreased with storage time at -20°C. Differences by age, sex and race were noted.
  
  
  CONCLUSIONS
  We recommend use of these creatinine-corrected markers and collection of timed overnight urine samples, stored at -70°C, with control for urinary flow rate, age, sex and race in statistical models.
authors.affiliation: New England Research Institutes, Watertown, MA 02472, USA. ftrachtenberg@neriscience.com
authors.forename: Felicia
authors.initials: F
authors.lastname: Trachtenberg
authors.forename: Lars
authors.initials: L
authors.lastname: Barregard
authors.forename: Nancy
authors.initials: N
authors.lastname: Maserejian
authors.forename: Sonja
authors.initials: S
authors.lastname: McKinlay
mesh_terms: D000704:Analysis of Variance; D002648:Child; D006801:Humans; D007668:Kidney / Q000502:physiology*; D007677:Kidney Function Tests; D008628:Mercury / Q000652:urine*; D013048:Specimen Handling
chemical_list: D008628:Mercury