Physicians often test for heavy metals using urine, whole blood, red blood cell, and less commonly, hair, or rarely, toenail samples [R].
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Blood Tests for Heavy Metals
In most cases blood testing is indicative of acute exposure rather than the total body burden (total amount of heavy metals accrued over one’s lifetime that is present in the body), however, there are exceptions [R].
Urine Testing for Heavy Metals
Urine testing is the gold standard for the “Big Four” toxic metals (mercury, arsenic, lead, and cadmium). However, even urine test can give an inaccurate representation of body burden for some metals, as they are often present in different forms, stored in different areas and processed by and excreted by the body differently [R].
For example, mercury is present in the body in two forms: organic (methylmercury or dimethylmercury) and inorganic (mercury salts, such as mercury chloride). Organic is largely excreted through the bile and feces, while inorganic is eliminated via the urine [R].
Therefore, whole blood is the preferred test for organic mercury body burden and urine testing is optimal for a measure of the body burden of inorganic mercury [R].
The Heavy Metals Challenge Test
A popular type of test is called the “challenge test”, or “provoked urine test,” which involves using large doses of a strong chelating agent, usually dimercaptosuccinic acid (DMSA), to draw metals out of the body and into the urine where they can be analyzed [R].
Chelation the process by which the body naturally binds toxic heavy metals in order to prevent them from causing harm and to excrete them from the body [R].
Chelation challenge tests are associated with adverse reactions, as the influx of mobilized metals can oftentimes overwhelm the body’s detoxification pathways as well as redistribute them to different or more critical tissues during the test [R].
Therefore, many professional and government organizations strongly recommend against their use because of this [R].
Despite this, the test is still commonly used by some practitioners. These clinicians argue that it allows them to determine the most effective chelating agent and to detect an absorption or tolerance problems with the agent [R].
If an individual decides to go the route of the challenge test, it is advised that their excretory pathways are open and not overburdened, i.e. in conditions like constipation or kidney and liver diseases, so as to allow the metals to pass out safely [R].
Additionally, urine samples should be taken pre- and post-challenge testing to establish a reference for the individual [R].
Instead of challenge testing, heavy metal toxicity is often diagnosed with a combination of reported symptoms and urine tests that reveal metal levels above the reference range [R].
Hair Testing for Heavy Metals
If done correctly, hair analysis is another reliable way to see if you have heavy metal toxicity [R]. Hair testing mainly reflects past exposure, so it should be combined with urine or blood testing to confirm heavy metal toxicity [R, R].