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1000
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Abstract/Summary
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The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has supplemented the definition of creatinine as reference parameter for the concentration of substances in urine. Barr et al. (2005) investigated the creatinine concentration of representative urine samples from the US general population (n = 22 245 persons, aged 6 up to > 70 years old, different ethnic groups). An evaluation focussing on the results for white, non‐hispanic volunteers in the age group 20–60 years, showed that approximately 10% of the creatinine concentrations in urine were outside the WHO reference range of 0.3–3 g/l. In agreement with the WHO criteria (1996) for biomonitoring in the field of occupational medicine, the Commission basically recommends using only those urine samples which have creatinine concentrations between 0.3–3 g/l for substance analyses and the assessment of individual measurements based on a statistically derived lower and upper reference value (5th or 95th percentile) for the creatinine concentration in urine. In addition, the working group “Setting of Threshold Limit Values in Biological Materials” considers it useful to continue to use the narrower target range of 0.5–2.5 g/l for urine samples, for further improving the reliability of analytical results with and without creatinine adjustment, and the validity of studies on the correlation between external and internal exposure. This aspect should already be considered in the preanalytical phase of a biomonitoring investigation.
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