The relationship between concentrations of ALA-U and Pb-S for two groups of workers is reported. The first group consisted of workers from a telephone company, and the second, of workers from battery factories with average Pb-S equivalent to 17,3 µg/dl (6,2-39,4) and 61,5 µg/dl (41,1-91,0), respectively. The aim of this study was to evaluate the utilization of ALA-U levels as a screening test for different levels of lead in blood by means of High Performance Liquid Chromatography (HPLC) and of spectrophotometry. A significant correlation was found between measured ALA and levels of blood lead (R = 0,739 - first group; R = 0,902 - second group; p < 0,001). The validity of ALA-U test to evaluate different levels of lead in blood was also studied. By using ALA levels of 3 mg/g creatinine as a threshold to detect levels of lead in blood equal to or higher than 20 µg/dl, the test results, for the workers in the first group, showed sensitivity of 92% and specificity of 90%. In both groups, the false positives as well as the false negatives were lower than 10%, which was enough to validate the test.
Lead Poisoning; Aminolevulinic Acid; Occupational Exposure; Occupational Health
