EVALUATING LEAD-EXPOSURE IN THE LABORATORY

Because the symptoms of lead poisoning are nonspecific, the clinical l aboratory plays a central role in the evaluation of exposure. Specimen collection requirements are stringent because of the ease of contamin ation with external lead. The preferred specimen is whole blood. Finge rstick blood is adequate for screening children, although elevated val ues should be confirmed with venous blood. Several agencies regulate l aboratories measuring lead, depending on the specimen type. Categories include clinical specimens, specimens from workplace exposure, and en vironmental specimens, such as drinking water. Government agencies set reference intervals for blood lead. The most important step in treatm ent of lead poisoning is to stop further exposure. Other steps include education, removal of lead from the environment, ensurance of proper nutrition, and the use of chelating agents. This is the first article in a four-part continuing education update series on toxicology. Other articles deal with alcohol, trace metals, and nonabusive causes of po sitive blood screens.