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Mercury, Urine and Blood
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25 de Abril de 2018.
At a Glance
Why Get Tested?
To detect excessive exposure to mercury
When To Get Tested?
When you have symptoms of mercury poisoning, to evaluate a known exposure to mercury, or to monitor occupational exposure to mercury
Sample Required?
A blood sample drawn from a vein in your arm and/or a urine collection
What is being tested?
Mercury is an element that exists in three forms: as a free metallic (liquid or vapor), an inorganic compound (mercury salt), and as a variety of organic compounds (the most common of which is methyl mercury). This test measures the amount of mercury present in blood, urine, or (rarely) hair to detect acute or chronic excessive exposure.

Mercury is found in small quantities throughout the environment. It is released by the breakdown of minerals in rocks and soils and as a byproduct of fossil fuel combustion and waste incineration. It is inhaled with the air that we breathe, absorbed through the skin, and ingested with food. The tiny amounts to which the vast majority of people are exposed to do not generally cause health concerns, but people who are exposed to dangerous concentrations of mercury (such as might be found at a hazardous waste site) or are exposed chronically to mercury (such as those who work with “heavy metals” in their occupation) may have mercury-related symptoms and complications.

Exposure to excessive amounts of mercury can be toxic. The amount of mercury absorbed by an individual and its effects on their health depends on the type of mercury, its concentration, and the exposure time. According to the Agency for Toxic Substances and Disease Registry (ATSDR), very little metallic mercury (less than 0.01%) is absorbed by the body, even if it is swallowed. However, if the same mercury is inhaled as a vapor, about 80% is absorbed into the bloodstream. About 95% of methyl mercury (the type found in fish and other seafood) is absorbed by the gastrointestinal tract. The most common source of human exposure to methyl mercury is as a result of eating contaminated seafood. Fish that come from contaminated waters and larger predator fish – fish that have eaten smaller fish – may have significantly increased levels of methyl mercury. This is why it is recommended that you know the source of the fish you consume and that you limit the quantity of large predator fish you eat.

Once mercury is absorbed, it finds its way into a variety of body organs, including the kidneys and brain. The body will slowly rid itself of mercury through the urine and stool, but if excessive amounts are present, it can permanently damage the kidneys, nervous system, and brain.

Pregnant women with elevated levels of mercury can pass it on to their fetus, affecting development, especially the fetus’s brain, kidneys, and nerves. Mercury can be passed from mother to baby through breast milk during nursing.

How is the sample collected for testing?

A blood sample is obtained by inserting a needle into a vein in the arm or a random or 24 hour urine sample may be collected. Rarely, another sample such as hair, breast milk, or nails may be tested.

Is any test preparation needed to ensure the quality of the sample?

No test preparation is needed. Consult your doctor or laboratory about urine collection to avoid sample contamination.
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Common Questions
  • How is it used?
    Mercury testing is done to detect the presence of an excessive amount of mercury. It may be ordered by your doctor to determine whether you have been acutely or chronically exposed to increased levels of mercury. It may also be ordered to monitor those who are exposed to mercury in the workplace.

    More than one type of sample may be collected and tested.

  • Blood is primarily tested to detect the presence of methyl mercury. Other forms of mercury can also be detected in the blood, but according to the Agency for Toxic Substances and Disease Registry (ATSDR), the amount present will decrease by half about every 3 days as the mercury moves into other organs.
  • Urine is used to test for metallic mercury and inorganic forms of mercury, but it cannot be used to determine exposure to methyl mercury.
  • Hair testing may be useful to detect methyl mercury exposures that occurred several months previously, but hair testing is relatively complex and is not used frequently.
  • Although not routinely ordered tests, mercury has been shown to be present in nails, breast milk, stool, and breath.
  • When is it ordered?
    Mercury testing may be ordered when a patient has symptoms suggesting excessive exposure to mercury. Acute symptoms may include:

  • burning in the mouth and lungs
  • cough, difficulty breathing, chest tightness
  • decreased urine output
  • nausea, vomiting, diarrhea
  • increased heart rate
  • Those who are chronically exposed may have nonspecific symptoms that involve the lungs, kidneys, and nervous system. Some of the chronic symptoms may include:

  • problems with hearing, taste and smell
  • blurry vision or sometimes tunnel vision
  • tingling or tremors in the arms or legs
  • difficulty walking
  • irritability
  • Testing may also be ordered when a patient is known to have been exposed to mercury to help evaluate the extent of the exposure. Mercury measurements may be ordered regularly as a monitoring tool for those patients who work in industries that utilize mercury and may be ordered, along with lead and/or other heavy metals, for individuals who work with a variety of potentially hazardous materials.