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Mercury (Blood)

Does this test have other names?

Hg level

What is this test?

This test measures the amount of mercury in your blood.

Mercury is a heavy metal that can be toxic. It occurs naturally as a liquid at room temperature and as an odorless vapor.

You can be exposed to mercury from polluted air or water. You can also be exposed if you work in an industry that still uses mercury, from eating fish that are high in mercury, and from some complementary and alternative health remedies. 

Long-term exposure to mercury can cause kidney and brain damage in adults. Exposure to mercury during pregnancy can cause permanent damage to the developing fetus. Breastfeeding may also expose infants to mercury.

Children who are exposed to mercury can suffer damage to their kidneys, nervous system, and digestive system.

Mercury is also in silver amalgam dental fillings. Tiny amounts of mercury may be absorbed from these fillings, but this amount is not likely to cause health problems.

Why do I need this test?

You may have this test if your healthcare provider suspects that you have mercury poisoning. Symptoms include:

  • Fever

  • Chills

  • Chest tightness

  • Shortness of breath

Inhaling mercury can cause:

  • Nausea

  • Diarrhea

  • Vomiting

  • Burning sensation in your mouth

You may also need this test to monitor your safety if it's possible that you could be exposed to mercury at your work. 

You may also have this test if you are pregnant or breastfeeding and have been exposed to high levels of mercury.

What other tests might I have along with this test?

Your healthcare provider may also order tests of your urine or breastmilk to measure for mercury. He or she may also test hair from your scalp to measure mercury exposure.

What do my test results mean?

Many things may affect your lab test results. These include the method each lab uses to do the test. Even if your test results are different from the normal value, you may not have a problem. To learn what the results mean for you, talk with your healthcare provider.

The results of this test are given in nanograms per milliliter (ng/mL). Having some mercury in your blood does not mean you will develop health problems.

Here is the breakdown on higher results:

  • 5 ng/mL: This may mean you are being exposed to unhealthy levels of mercury at your work or in your diet.

  • 30 to 40 ng/mL: This level usually causes some symptoms and some brain or kidney damage.

  • Above 100 ng/mL: This is considered mercury poisoning.

How is this test done?

The test requires a blood sample, which is drawn through a needle from a vein in your arm.

Does this test pose any risks?

Taking a blood sample with a needle carries risks that include bleeding, infection, bruising, or feeling dizzy. When the needle pricks your arm, you may feel a slight stinging sensation or pain. Afterward, the site may be slightly sore.

What might affect my test results?

Certain Chinese herbal products or skin-lightening creams that contain mercury can cause your blood level to rise. Eating fish and shellfish that contain high levels of mercury can raise your mercury levels.

How do I get ready for this test?

You don't need to prepare for this test.


Mercury (Blood) - WellSpan Health

Author: Orenstein, Beth W
Online Medical Reviewer: Taylor, Wanda L, RN, PhD
Online Medical Reviewer: Ziegler, Olivia Walton, MS, PA-C
Last Review Date: 2015-08-30T00:00:00
Last Modified Date: 2015-09-18T00:00:00
Published Date: 2015-09-18T00:00:00
Last Review Date: 2012-06-18T00:00:00
© 2015 WellSpan Health. All Rights Reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.

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