Study of preanalytical conditions for selenium determination in urine

Objective: Assessment of preanalytical and storage conditions for selenium determination in urine. Design and method: A design is established for the study of the effect of HCl as sample preservative, and for the stability of urine samples with time and temperature of storage. The effect of sample sonication before taking aliquots is also evaluated. All measurements are performed using hydride generation atomic fluorescence spectrometry. Selenium concentrations measured from 52 urine samples of healthy population in Barcelona are used for an estimation of the selenium reference level. Results: HCl addition to urine samples has no effect on Se stability. Significant differences are due to time and temperature of storage. The Se reference level in urine samples from population in Barcelona area is estimated to be 22.8 _ 6.7 _g Se gCT _1 (CT: creatinine). Conclusions: No significant differences are observed in selenium content when HCl is added as preservative. The Se content remains constant at room temperature for one day, for a week at 4°C and for a fortnight when stored at _20°C. © 2001 The Canadian Society of Clinical Chemists. All rights reserved.