Heavy Metal Toxicity Workup

Updated: Mar 10, 2023
  • Author: Adefris Adal, MD, MS; Chief Editor: Sage W Wiener, MD  more...
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Approach Considerations

The first priority in managing any patient with detectable serum lead is to determine the source of exposure and to remove the person from it. The finding of any elevated serum or urine metal concentration in an asymptomatic person should prompt a thorough dietary, occupational, and recreational history, and radiographs where indicated to identify any source of ongoing exposure. Occupational or recreational histories in parents can also reveal a source of exposure for children.


Laboratory Studies

Specific laboratory testing for metals should be undertaken when the likelihood of toxicity is significant, based on a history and/or symptoms consistent with excessive exposure. See the relevant articles for more detailed recommendations regarding the most reliable testing measures for individual metal toxicity, as follows:

When specific testing is indicated, samples should be sent in metal free containers.

Hair analysis is not generally reliable and rarely indicated.

Patients should be instructed to abstain from seafood and seaweed products prior to testing for metals such as arsenic and mercury, since elevated concentrations in patients who have not done so for at least several days to 1-2 weeks may simply reflect nontoxic organic forms ingested in the diet. Samples with elevated concentrations may also be sent for speciation for either of these metals to determine the relative contributions of organic forms versus inorganic forms.

The following standard laboratory determinations may help make the diagnosis of heavy metal toxicity or help gauge its severity:

  • Complete blood cell count (CBC) with peripheral smear - Findings may include basophilic stippling of the RBCs on peripheral blood smears; basophilic stippling is not specific for lead toxicity and may be observed in arsenic toxicity, sideroblastic anemia, and thalassemia; the anemia of lead toxicity may be normocytic or microcytic.
  • Renal function tests
  • Urine analysis (look for proteinuria)
  • Liver function studies

Imaging Studies

Abdominal radiographs are indicated in acute ingestions. Radio-opacities demonstrable in the gastrointestinal tract should be cleared by whole-bowel irrigation prior to instituting chelation therapy. Large, retained gastric foreign bodies (eg, bullets, shotgun cartridges, fishing sinkers, curtain weights) may cause lead toxicity and should be removed endoscopically if they do not pass, if serum lead concentrations are concerning or increasing, or if the patient becomes symptomatic.

Several reported cases of patients who have injected elemental mercury subcutaneously and developed mercury toxicity have been documented. Radiographs of the suspect areas showing large subcutaneous deposits of radio-opaque material were helpful in confirming the diagnosis and need for surgical intervention to limit the exposure.


Other Tests

Electrocardiographic abnormalities may provide diagnostic clues in metal toxicity.