Significance and validity of a shortened lead chelation test

We evaluated the chelation test in 38 subjects exposed to lead or with suspected lead exposure, comparing the values of lead excretion at the 3rd h (PbU EDTA/3-h) and at the 24th h (PbU EDTA/24-h) after EDTA administration. Good correlation exists between PbU EDTA/3-h and PbU EDTA/24-h (r = .86) and between them and the main biological indicators of dose and effect of lead. When a second chelation test was performed in 15 subjects, a slightly better r coefficient (.93) was observed between the two tests, without reaching statistical significance. It seems difficult, in terms of the type of exposure that we considered, to use the 3-h test, on an individual basis, to predict the PbU EDTA/24-h values.