Mercury Test-Why am I having this test?

Mercury (Hg) is a metal that can be harmful to your health if you are exposed to a lot of it. There are several different forms of mercury that are present in small amounts throughout the environment. You may have this test if:

• You are regularly exposed to mercury at your job.
• You have signs of mercury exposure or very high mercury levels (mercury poisoning), such as:
  • Coughing and trouble breathing.
  • A feeling of tightness in the chest.
  • Problems urinating.
  • A burning sensation in the lungs or mouth.
  • Nausea and vomiting.
  • Diarrhea.
  • Increased heart rate.
  • Fever or chills.
  • Dizziness.
  • Headaches.
  • Increased salivation.
  • Sores in the mouth.

What is being tested?

This test measures the amount of mercury in your blood or urine. Mercury has three different forms, and this test may be done to check the amount of one, two, or all three of these forms:

• Elemental mercury. This is a thick, silver liquid at room temperature. It can be found in thermometers, dental fillings, and light bulbs.
• Organic mercury. This can build up in the bodies of certain large fish, like sharks and swordfish. The main type of organic mercury is called methylmercury.
  • If you may have been exposed to methylmercury from eating fish, it is important to get tested soon after eating the fish. Methylmercury levels in the blood will lower within a few days as the mercury moves to the kidneys and brain.
• Inorganic mercury. This type is found in batteries, disinfectants, and creams.

What kind of sample is taken?

The kind of sample taken depends on what forms of mercury are being tested.

• A blood sample is needed to check for methylmercury. The blood sample is usually collected by inserting a needle into a blood vessel.
• A urine sample is needed to check for elemental mercury and inorganic mercury.
  • You may be asked to collect urine samples at home over a period of 24 hours.
  • A urine test is often done for people who are exposed to mercury at their job because urine provides information about mercury exposure over time.
• Both a blood sample and urine samples may be collected to check all three forms of mercury.

How do I collect samples at home?

When collecting a urine sample at home, make sure you:

• Use supplies and instructions that you received from the lab. 
• Collect urine only in the germ-free (sterile) cup that you received from the lab. 
• Do not let any toilet paper or stool (feces) get into the cup.
• Refrigerate the sample until you can return it to the lab. 
• Return the sample(s) to the lab as instructed.

How do I prepare for this test?

Tell your health care provider about all medicines you are taking, including vitamins, herbs, eye drops, creams, and over-the-counter medicines. Follow instructions from your health care provider about changing or stopping your regular medicines. This is especially important if you are taking diabetes medicines or blood thinners.

How are the results reported?

Your test results will be reported as values. These will be given as micrograms of mercury per liter of blood or urine (mcg/L). Mercury is commonly abbreviated as Hg.

Your health care provider will compare your results to normal ranges that were established after testing a large group of people (reference ranges). Reference ranges may vary among labs and hospitals. For this test, a common normal reference range is 0–10 mcg/L.

What do the results mean?

A result that is within the reference range is considered normal, meaning that you have a normal amount of mercury in your body.

A result that is higher than the reference range means that there is too much mercury in your body. This may mean that you have recently been exposed to an unsafe amount of mercury. If your level is very high, you may have mercury poisoning. Mercury exposure or poisoning can:

• Harm the kidneys, heart, and nervous system.
• Cause skin rashes.
• Cause memory problems.
• Harm a growing baby, either during pregnancy or during breastfeeding.
• Cause developmental delays in children.

Mercury poisoning is an emergency that must be treated immediately. It requires treatment to remove the mercury from your body.

Talk with your health care provider about what your results mean.

Questions to ask your health care provider

Ask your health care provider, or the department that is doing the test:

• When will my results be ready?
• How will I get my results?
• What are my treatment options?
• What other tests do I need?
• What are my next steps?

Summary

• Mercury (Hg) is a metal that can be harmful to your health if you are exposed to a lot of it. Mercury can be found in thermometers, dental fillings, light bulbs, and certain large fish, like sharks and swordfish.
• This test measures the amount of mercury in your blood or urine.
• A result that is greater than the reference range means that there is too much mercury in your body. This is a medical emergency that must be treated immediately.
• Talk with your health care provider about what your results mean.