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Stricter regulations and controls for environmental lead have resulted in significantly lower frequency and reduced severity of chronic and acute lead intoxication. The aim of the present study was to update established reference ranges for lead in whole blood of healthy adults residing in Zaragoza and its region in northeastern Spain. The mean blood level was 2.94 +/- 2.02 microg/dl, with a median of 2.43 microg/dl (n = 156). For women, the mean was 2.29 +/- 1.64 microg/dl (n = 73) and for men 3.51 +/- 2.16 microg/dl (n = 83). The difference between genders is statistically significant (p < 0.005). Our results confirm an ongoing decline in blood lead levels in the studied region, which in 1989 were found to average 13.17 +/- 3.47 microg/dl. In addition, there is a clear need to take into account gender differences when defining normal ranges for lead.

ISO 15189 standard establishes a requirement to periodically revalidate analytical methods for the determination of trace elements like Pb in blood, as conditions change and technical advances are made. The aim of this study was to revalidate an electrothermal atomic absorption spectrometry (ETAAS) method for determination of Pb in blood over the microrange 25-35 microg/dL, on the basis of historical results of interlaboratory comparison programmes. Precision and inaccuracy were estimated by analysis of records of an external quality control programme for Pb (PICC-PbS). The precision and inaccuracy values obtained were both less than 5%, highly satisfactory in view of the validation requirement that precision and inaccuracy be less than 10%. These findings demonstrate the effectiveness of this new validation methodology, which does not require any disruption of the laboratory's routine activity, and which can be used even if the method in question has not been validated previously at that laboratory.