WHAT IS LEAD TEST?
Lead is a heavy metal that is used in paint, leaded gasoline, insecticides, pottery glaze, and illicit liquor and is found in the fumes of old painted wood. It is an electropositive metal that has an affinity for the negatively charged sulfhydryl group and inhibits three enzymes in the body: delta-aminolevulinic acid dehydrase, coproporphyrinogen oxidase, and ferrochelatase. These enzymes are necessary for the production of heme, the iron-containing portion of haemoglobin. The majority of lead in the body is stored in the skeletal system and is thought to be released into the bloodstream in increasing amounts during periods of accelerated bone turnover and mineral loss. The acceptable levels for blood lead content have been gradually lowered over time as new information on lead’s detrimental effects has become available. Lead measurements are performed on whole-blood specimens because whole-blood concentrations are 75 times higher than those of plasma or serum. Exposure of children to low levels of lead has been associated with reduced intellectual and neuropsychologic development. For this reason, many communities have in place routine screening for lead exposure of all schoolchildren. This test is the most appropriate test in screening for elevated lead levels in children and in workers in close contact with lead-containing substances.