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Why get tested?
To screen for, detect, and monitor excessive exposure to specific heavy metals
When to get tested?
Periodically when you work with heavy metals, or when your doctor suspects that you mayhave been exposed
Sample required?
A blood sample drawn from a vein in your arm or a 24-hour urine sample; rarely, a hair sample, tissue sample, or another body fluid sample
What is being tested?
A heavy metals panel is a group of tests that measures the quantity of specific, potentially toxic metals in the blood, urine, or more rarely in the hair or another body tissue or fluid. A laboratory may offer several different groupings of heavy metals panels as well as tests for individual metals. The most common combination includes lead, mercury, and arsenic. Other panels may include one or more additional metals, such as cadmium, copper, and zinc. Your doctor will select which metals to test for based upon what you may have beenexposed to and your clinical symptoms.
The term "heavy metals" is loosely defined. It is related to the periodic table of elements and refers to a variety of elements with high density or metallic properties. These elements are found naturally throughout the environment and are also used by industries to manufacture a wide range of common products. Some of them, such as iron, copper, selenium, molybdenum, and zinc, are required in trace amounts by the body for normal function but can be toxic at higher levels. Significant concentrations of any of the heavy metals can be irritating or damaging to humans and can contaminate soil, air, food, and water and can persist indefinitely in the environment. Because they are a source of potential injury, the termheavy metals is frequently used interchangeably with the term "toxic metals."
The signs and symptoms that a person may experience depend on the type of metal, its form, the quantity, the length of exposure, the type of exposure, the age of the person, and their general state of health. Some metals are much more toxic than others, and one form ofmetal may be more harmful than other forms, such as an organic versus inorganic metal compound. How a person is exposed can influence the amount of metal absorbed and the part(s) of the body that are affected. A metal that does little when it is held in someone’s hand, or is only moderately harmful and poorly absorbed when swallowed, may be muchmore toxic and cause severe lung damage when its vapors are inhaled.
Severe acute exposure can cause damage and, in some cases, can be life-threatening, but so can moderate exposures over time. The body is able to rid itself of small amounts ofheavy metals, but moderate to large quantities can accumulate in the kidneys, the liver, the bones and the brain. Some metals are considered carcinogenic – they increase the risk of developing cancer. Some can affect the body’s ability to produce red and white blood cells. Fetuses and young children are at the highest risk. Even exposures to low or moderateconcentrations can affect physical and mental development in the young and, in some cases, can permanently damage the organs and brains. Many of the metals can be passed from the mother to the fetus, and some can be passed to the infant in breast milk.
How is the sample collected for testing?
Heavy metal testing is usually performed on a blood sample obtained by inserting a needle into a vein in the arm or on a 24-hour urine collection. Special metal-free blood or acid-washed urine containers are used to minimize the potential for sample contamination by any outside sources of metal.
Urine and blood can both be used for heavy metal testing, but they do not necessarily test for the same forms of the metal. For instance, methyl mercury – organic mercury found in fish – can be detected in the blood but not in urine. Urine is the preferred sample for measuring inorganic forms of mercury and for measuring arsenic.
Hair and fingernail analysis can give an indication of exposure that has occurred over time or in the past but will not show recent exposures. Blood and urine will reflect exposures that are chronic or that have happened in the last few days.
In rare cases, a biopsy will be performed to obtain a tissue sample for testing.
How is it used?
Heavy metals panels are used to screen for or to diagnose heavy metal poisoning inthose who may have been acutely or chronically exposed to one or more heavy metals and to monitor excessive metal concentrations in those who work with various heavymetals. Panels are set up in groups of tests that mirror potential metal exposures. A laboratory may offer several different groupings that are specific for either blood or urine. Your doctor will order the metals panel that corresponds to your occupation, hobby, suspected exposure, and/or clinical symptoms. Some of the metals that are more commonly tested include:
- Lead
- Mercury
- Arsenic
- Cadmium
- Chromium
If your doctor suspects that you have been exposed to a specific metal, such as lead, then she may order that specific test instead of or in addition to a panel. Lead is usually ordered by itself when screening for exposure in young children. Some metals can also be measured in fluid, hair, fingernails, and body tissues. Usually these are ordered individually.
A zinc protoporphyrin (ZPP) test may be ordered, along with a lead level, to test for chronic lead exposure in adults. However, it is not as widely ordered by doctors as in the past. The ZPP test result increases with lead exposure because lead interferes with the red blood cells' ability to make hemoglobin. It reflects an average of lead exposure over time but not recent exposure. However, it does not usually become abnormal until the lead concentration is greater than 25 micrograms per deciliter. Because values do not rise until leadconcentrations exceed the acceptable range, ZPP is not sensitive enough for use as a screening test in children.
Other tests, such as a Complete Blood Count (CBC) to evaluate blood cells and check for anemia or a Comprehensive Metabolic Panel (CMP) to evaluate body organ function and electrolyte balance may be ordered along with metal analysis to evaluate a person’s general state of health.
When is it ordered?
A heavy metals panel may be ordered if your doctor suspects that you have been acutely or chronically exposed to one or more heavy metals. Signs and symptoms of heavy metal exposure will vary in nature and intensity depending on the type and quantity of metal involved; early symptoms of poisoning can be missed because they are often non-specific.Excessive exposure and damage to several different organs can occur even if you have no, few, or nonspecific symptoms. Some signs and symptoms of metal poisoning may include:
- Abdominal pain, nausea, vomiting, and diarrhea
- Nervous system symptoms such as numbness, tingling of hands and feet, weakness
- Anemia
- Kidney damage
- Liver damage
- In the lungs – irritation, edema
- Brain dysfunction, memory loss
- Changes in behavior
- Malformed bones in children, weakened bones
- In pregnant women – miscarriage, premature labor
People who may be exposed to metals in the workplace are usually monitored periodically. Safety measures are in place to minimize the risk to employees and to address problems when they are identified. The U.S. Occupational Safety and Health Administration (OSHA) regulates the use and monitoring of thirty-five toxic metals that may be found on the job. Ifexcessive concentrations are detected, the affected person will be monitored as steps are taken to reduce their exposure.
What does the test result mean?
Care must be taken in the interpretation of heavy metals tests. A low level of a heavy metal in the blood does not necessarily mean that excessive exposure has not occurred. Heavy metals do not stay in the blood and will not be present in the urine for extended periods of time. Lead, for instance, migrates from the blood into the body’s organs and over time is incorporated into the bones. If someone was chronically exposed to lead, then he might have lead in his blood, urine, organs, and bone.
Very low levels of many heavy metals may be present in the blood and urine of apparently healthy people because these metals are present throughout our environment. Recommendations for safe levels of heavy metals depend on the age of the person and may change over time as more information about their safety emerges.
Is there anything else I should know?
Hobbyists who work with various metals need to be aware of the potential risk of exposure to heavy metals and their toxic effects.
Exposures to the same amounts and types of heavy metals will not necessarily lead to the same effects in different people. People absorb and eliminate metals at different rates.Those who have underlying health conditions may be more vulnerable than others to the same exposures. Depending on symptoms or tests results from a certified laboratory, those with levels higher than what is considered to be safe may consider chelation therapy. Chelation therapy is a treatment to rid the body of high amounts of a heavy metal.
Trace concentrations of heavy metals are monitored and minimized but are almost impossible to avoid altogether. For instance, naturally-occurring arsenic is a contaminant that can be found in some sources of drinking water throughout the world. Small amounts of mercury are found in fluorescent light bulbs and some thermometers. If these break, the mercury can be released. Methyl mercury, an organic form of mercury that is produced by bacteria in water, can build up in fish over time. Concentrations vary regionally and with the size of the fish. The highest levels are typically found in bigger and older fish. In most cases, the benefits of eating fish outweigh the small risk of ingesting excess mercury. However, women who are pregnant may want to take extra precautions. The March of Dimes recommends that pregnant women avoid certain types of large fish during their pregnancy because of mercury’s potential harm to the fetus.
Lead was once routinely used in paint, plumbing pipes, and as an additive in gasoline. In the U.S., these environmental sources of lead have decreased, but it can be present in the existing paint and plumbing of older homes and is sometimes present in the paint of imported toys or jewelry. When lead house paint deteriorates, it creates lead chips and dust that can be stirred up with the movement of air and can find their way into the soil around the house. While anyone may be harmed by lead exposure, children are at the highest risk. They may eat paint chips, mouth painted surfaces, breath in lead dust, and play in contaminated soil.
All of the sources of heavy metal exposure in the air, water, food supply, and in the environment are controlled, regulated, and monitored by both governmental agencies and the medical community. The Environmental Protection Agency (EPA) evaluates the effects of exposures, regulates industrial emissions, and establishes maximum contaminant levels forheavy metals such as arsenic in drinking water. The Food and Drug Association (FDA) establishes limits for metals in food, and the Centers for Disease Control and Prevention (CDC) recommends testing young children for lead, especially for those who live in or routinely visit a house built before 1950.
Common Questions
- How long will it take to get the results of my test?
Heavy metal analysis is not done on a routine basis and is frequently performed at a reference laboratory, so the results are likely to take several days.
- How is someone exposed to toxic metals?
Heavy metals can enter the body through the skin or by inhalation or ingestion. Toxicity occurs when the metals displace the essential elements in the body and begin to affect the normal function of various organs. Most people will never be sufficiently exposed to be harmed or require testing. The majority of acute and chronic exposures occur in the workplace, especially in industries that use metals to manufacture products; such as the cadmium, lead, and mercury used in batteries and the arsenic used in some pesticides. Exposures can also occur in agricultural workers, in people whose job it is to clean up contaminated environmental sites, inthose who work with certain products – such as auto mechanics working with car batteries, and in those with hobbies that involve the use of metals – such as the leadused by stained glass artisans. Most exposures to excessive concentrations in the general population are primarily due to increased levels of metals in food or water, products that they use, or soil contamination in or near the areas that they work and live.
- How can I test my soil, water, or the paint on my house for heavy metals?
See the related links and explore the Environmental Protection Agency website. The EPA has information that can help you find a professional to evaluate your environment.
- In addition to lead, mercury, arsenic, cadmium and chromium, what are some othermetals that may be tested?
Some metals that are tested less frequently in suspected toxicity include:
- Aluminum
- Beryllium
- Cobalt
- Copper
- Iron
- Manganese
- Nickel
- Platinum
- Selenium
- Silicon
- Silver
- Thallium
Information courtesy of Lab Tests Online.