Lead in blood
Protoporphyrin in erythrocytes
Springer Online Journal Archives 1860-2000
Summary In previous research we established that FEP is a suitable and valid test for evaluating the metabolic damage caused by lead absorption. In this study, in the same sample consisting of adult male subjects with PbB levels ranging from 15 to 150 μg/100 ml, we examined the relationship existing between PbB and the other indicators of effect so as to compare their behavior with that of FEP and establish whether there is a field of application where the erythrocyte metabolite is to be preferred. FEP and ALAD displayed a very much better correlation with PbB than the urinary tests (ALAU and CPU). The decrease in ALAD values is already clear at PbB levels which do not cause an elevation of FEP; on the other hand, when the enzyme is markedly inhibited, the erythrocyte metabolite is elevated further with the increase in the internal lead load. FEP increases earlier compared to ALAU and CPU; nevertheless, the urinary metabolites undergo increasing elevations at PbB levels higher than 90 μg/100 ml when the FEP values have become stable. We confirmed that FEP possesses good predictive validity at PbB levels of 60 and 70 μg/100 ml; for such PbB levels, also ALAD, measured with the European Standardized Method, displayed high validity. Validity of the urinary metabolites was rather modest. FEP was, moreover, well correlated also with other indicators, suggesting that the erythrocyte metabolite may be used to predict both dose and effect.
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