Studies in lead poisoning. Comparison between different laboratory tests

Abstract

The urinary output of δ-aminolaevulic acid (ALA), coproporphyrins, and lead in 15 leadintoxicated workers was determined and correlated with the degree of intoxication. Raised levels of ALA in the urine show the best agreement with clinical evidence of intoxication.

In addition these values were correlated with the amount of lead excreted after treatment with a total dosage of 9 g. penicillamine. Weak correlations were found between therapeutically excreted lead and initial values for lead and coproporphyrin in urine. In contrast the initial values for ALA correlate very closely (P < 0·001). It is concluded that determinations of the output of ALA are to be preferred in the evalution of lead intoxication and that they point directly to the amount of metabolically active lead in the organism.