title: Erythrocyte delta-aminolevulinic acid dehydratase activity as a measure of lead exposure.
abstract: The measurement of erythrocyte delta-aminolevulinic acid dehydratase (ALA-D) activity has been found to be a useful guide to lead exposure for screening purposes. The pH of the test should be well-controlled for adequate clinical interpretation. False-normal tests are rare even with iron-deficiency anemia or macrocytosis. Recent transfusion and recent bleeding or hemolysis with reticulocytosis tend to invalidate the test. ALA-D activity above 600 International Units effectively excludes significant lead exposure and eliminates the need for further testing. ALA-D activity is maximally depressed at a red cell lead concentration of 200 mug per 100 ml. When activity is moderately depressed, interpretation is difficult and the urinary excretion of lead after the administration of a chelating agent is usually required to differentiate the degree and significance of lead exposure.
mesh_terms: D000368:Aged; D000437:Alcoholism / Q000097:blood / Q000201:enzymology; D000747:Anemia, Hypochromic / Q000097:blood / Q000175:diagnosis / Q000201:enzymology; D004781:Environmental Exposure; D004912:Erythrocytes / Q000201:enzymology*; D004913:Erythrocytes, Abnormal / Q000201:enzymology; D006801:Humans; D006836:Hydro-Lyases / Q000097:blood*; D006863:Hydrogen-Ion Concentration; D007854:Lead / Q000097:blood*; D007855:Lead Poisoning / Q000097:blood / Q000175:diagnosis / Q000201:enzymology; D008297:Male; D008403:Mass Screening; D000623:Porphobilinogen Synthase / Q000097:blood*
chemical_list: D007854:Lead; D006836:Hydro-Lyases; D000623:Porphobilinogen Synthase