When performed as described, the edathamil calcium disodium (Versenate) diagnostic test provided clear-cut differentiation between normal individuals and those with increased exposure to lead. The average excretion of lead in urine in the 24 hours after administration of the drug was 165 µg/l in normal children, 995 in those with suspected lead poisoning, and 1,966 in those with classic lead poisoning. We have no evidence, of course, that the children with the triad of pica, basophilic stippling and high excretion of lead after administration of the drug would have gone on to develop the classic findings of lead poisoning if exposure to lead had continued; it seems to be a reasonable assumption. The preventive medicine approach to lead intoxication marks these children as the group that might benefit most from therapy.
As a result of these studies we have evolved the following approach to lead intoxication: (1) Children with the classic symptomatology of lead poisoning, or with unexplained central nervous system disease, and laboratory confirmation of the diagnosis should be treated by the recommended method. (2) All children with pica and all children with basophilic stippling should be considered as potential victims of lead poisoning. (3) If the diagnostic test demonstrates an excretion of lead in urine of more than 500 µg/l, there has been excessive ingestion of lead-containing substances. (4) When a child has excessive excretion of lead after administration of edathamil calcium disodium, special efforts should be made to remove him from the source of exposure, as a preventive measure. A course of therapy with edathamil may be indicated for these patients.