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.

Keywords::

• methodological study
• albumins
• gamma-glutamyltransferase
• acetylglucosaminidase
• child

Acknowledgements

We thank Thomas Lundh at the Department of Occupational and Environmental Medicine, University of Lund, Sweden, for the analyses of mercury in the substudy.

Declaration of interest

The authors report no declarations of interest. This study was supported by a cooperative agreement (U01 DE11886) between the New England Research Institutes and the National Institute of Dental and Craniofacial Research, National Institutes of Health.