From the FDA Drug Label
The diagnosis, if suspected on the basis of family or individual history or physical examination, can be confirmed if the plasma copper-protein ceruloplasmin** is less than 20 mg/dL and either a quantitative determination in a liver biopsy specimen shows an abnormally high concentration of copper (greater than 250 mcg/g dry weight) or Kayser-Fleischer rings are present The sulfhydryl groups of dimercaprol form complexes with certain heavy metals thus preventing or reversing the metallic binding of sulfhydryl-containing enzymes.
An abnormal result on a heavy metals screen is considered when the levels of certain heavy metals, such as copper, exceed the normal range.
- For copper, an abnormally high concentration is greater than 250 mcg/g dry weight in a liver biopsy specimen.
- Additionally, a plasma copper-protein ceruloplasmin level less than 20 mg/dL may indicate an abnormal result. It is essential to note that the interpretation of a heavy metals screen should be done by a qualified healthcare professional, taking into account the individual's medical history, physical examination, and other diagnostic tests 1, 2.
From the Research
An abnormal result on a heavy metals screen is typically defined as levels exceeding established reference ranges, indicating potential toxicity, with thresholds including lead above 5 μg/dL, mercury exceeding 10 μg/L in blood, arsenic over 50 μg/L in urine, and cadmium above 5 μg/L in blood, as reported in the most recent study 3.
Interpretation of Heavy Metals Screen
When interpreting a heavy metals screen, it is crucial to consider the established reference ranges for each metal, as exposure to these substances can have significant health implications. The reference ranges are as follows:
- Lead: above 5 μg/dL in adults or children
- Mercury: exceeding 10 μg/L in blood
- Arsenic: over 50 μg/L in urine
- Cadmium: above 5 μg/L in blood These thresholds are based on the most recent study 3, which provides an overview of the physical properties, common sources of exposure, basic toxicokinetics, and health effects of heavy metals.
Health Implications of Heavy Metal Exposure
Exposure to heavy metals can have severe health consequences, including neurological issues, kidney damage, gastrointestinal problems, and developmental delays in children, as discussed in 4. The severity of the abnormality depends on how much the level exceeds the reference range, with higher concentrations generally indicating greater risk of toxicity.
Follow-up and Treatment
If an abnormal result is detected, follow-up testing is typically recommended to confirm findings, identify the source of exposure, and determine appropriate treatment, which might include chelation therapy for significant elevations, as suggested in 5 and 6. Regular monitoring may be necessary for those with occupational exposure risks.
Elimination of Heavy Metals
Research has also explored the elimination of heavy metals from the human body, with studies suggesting that induced micturition and sweating may be potential methods for eliminating bioaccumulated heavy metals, as reported in 7. However, this area requires further investigation to fully understand its implications for clinical practice.