Heavy Metal Blood Tests: What Patients Need to Know

Note: This is an educational blog post about heavy metal blood tests and does not constitute medical advice. Consult a qualified medical practitioner for any health concerns.

In our last article, we presented the key scenarios that warrant heavy metal testing and explored the various methods used today. Here, we take a deeper dive into heavy metal blood tests, covering what they are, how they work and what the results can tell healthcare providers.

What is a heavy metal blood test?

A heavy metal blood test checks for the presence of potentially harmful metals in the body.

A healthcare provider usually orders a heavy metal blood test for individuals who have been exposed to heavy metals through their work (occupational exposure) or environment, individuals who display symptoms of heavy metal toxicity following a known or suspected exposure, and for high-risk populations such as pregnant individuals and young children living in areas with lead contamination.

Heavy metals can enter the body in several ways, including ingestion, inhalation and absorption through the skin. Because the symptoms of heavy metal poisoning often overlap with other conditions, blood testing is necessary to confirm an exposure and implement the best course of treatment as soon as possible after the exposure has occurred.

What exactly does a heavy metal blood test measure?

A heavy metal blood test measures the concentrations of certain heavy metals in the blood. The results of the test inform the healthcare provider about which heavy metal(s) someone has been exposed to in the previous few days, weeks or months and provides indications about the severity of the exposure.

The metals most commonly included in these tests include lead, mercury, arsenic, cadmium and chromium, although others, such as aluminum, copper, iron and nickel, may be included depending on what the person has or may have been exposed to.

Again, depending on the exposure risk, a blood test may measure only one type of metal or a panel of different metals. As a side note, a heavy metal blood test may also be referred to as a heavy metal panel or a heavy metal toxicity test.

Preparing for the test

Besides informing the healthcare provider about medications, supplements and vitamins being used, some specific preparations are required before heavy metal blood testing. Importantly, the person being tested will be advised not to consume seafood for 48 hours prior to blood sampling; this is to avoid a false positive result caused by the presence of trace amounts of heavy metals in certain seafoods. Fasting is not usually required.

In addition, testing is typically not carried out within 96 hours after MRI tests that involve the use of gadolinium, barium or iodine-based contrast liquids since these may interfere with certain heavy metal tests.

What happens during a heavy metal blood test?

Heavy metal blood tests are usually carried out at medical facilities because they require the presence of a trained phlebotomist to take blood samples. Blood is usually taken as a venous blood draw, i.e., from a vein in the arm, using a small needle to puncture the vein. A small volume of the blood is then collected in a test tube for testing in the analytical lab.

The blood sampling procedure itself is relatively short, usually taking about five minutes. Results are usually available within a few days after the samples have been sent to the lab.

Blood tests differ depending on the metal(s) being tested

Heavy metal blood tests vary in methodology depending on which metals are being assessed and what type of exposure is suspected. The main testing approaches include:

Whole blood testing. This is used for lead, cadmium, and mercury. Here, the entire blood sample is analyzed, including red blood cells where many heavy metals concentrate.

Serum/plasma testing. This approach is used for arsenic, aluminum, and some forms of mercury. For the individual being tested, the blood sampling procedure is the same; the collected blood is then separated into cells and plasma, and the plasma is analyzed for the heavy metal(s).

Red blood cell testing. This method specifically measures metals within red blood cells and is typically used to measure blood concentrations of selenium, zinc, and copper, which are primarily found in red blood cells rather than serum.

Speciated testing. This approach refers to tests that can differentiate between different chemical forms of the same metal, e.g., organic vs. inorganic mercury or arsenic, which have different toxicity profiles.

What do the blood test results mean?

The results of a heavy metal blood test show the measured level for each metal included in the test as well as a laboratory reference range for each metal. These results provide an indication of the risk category for the person being tested, i.e., whether the blood metal concentration is normal (i.e. within the reference range), elevated or significantly elevated.

Blood tests that indicate elevated heavy metal concentrations are generally followed up with a confirmatory (repeat) test and exposure investigation to identify and remove the source of exposure. The individual may undergo additional medical tests to assess the impact of exposure on overall health and determine the best course of treatment.

No universal source exists for heavy metal reference ranges, but the accepted ranges for some of the most common heavy metals are:

Lead: While the U.S. Centers for Disease Control and Prevention (CDC) state that there is no safe level of lead in the blood, a blood lead concentration of <5 μg/dL of blood is considered acceptable in adults, while the reference cut-off for children is <3.5 μg lead per dL of blood.

Mercury: <10 μg/L for whole blood is considered typical according to the World Health Organization and U.S. Environmental Protection Agency.

Arsenic: According to the American Conference of Governmental Industrial Hygienists (ACGIH), a blood arsenic concentration of <10 μg/L is considered within the normal range. However, because arsenic is rapidly cleared from the blood, urine testing may be used in conjunction with blood testing to get a more reliable indicator of the severity of arsenic poisoning following exposure.

Cadmium: According to the U.S. Agency for Toxic Substances and Disease Registry and other laboratory standards, the reference range for cadmium within the non-smoking, general population is < 1.0 μg/L, while that increases to < 3.0 μg/L in smokers. The cut-off for occupational biological exposure is < 5.0 μg/L.

How much does a heavy metal blood test cost?

The cost of a heavy metal blood test varies between countries and depends on how many metals are included in the panel as well as how many tests are performed at once. For example, the cost per test may be lower for a large screen of high-risk individuals than for an individual who requires a single heavy metal test.

Heavy metal blood tests are provided by national healthcare systems and are often covered by private health insurance policies when deemed medically necessary and ordered by a healthcare professional.

A number of direct-to-consumer heavy metal testing services and home/DIY metal testing kits (e.g. for lead) are also available; the former are typically processed in independent, commercial laboratories and tend to be more costly than when carried out in the healthcare system. Perhaps not surprisingly, DIY heavy metal testing kits are considered to be less accurate than testing carried out in healthcare- or commercial testing facilities.

Innovation in heavy metal blood testing

Advances in testing technology continue to make heavy metal blood tests more accessible. At Capitainer’s new miQro laboratory in Rhode Island, our scientists have developed a heavy metal testing panel including lead and other toxic metals that is being optimized for microsamples to offer more easily accessible blood testing solutions. This solution offers the possibility for at-home, self-sampling with the same quality as tests carried out in the healthcare system. These innovations may help expand testing capabilities, particularly in areas where traditional venous blood collection presents challenges. To learn more about these tests, please feel free to send an email to the lab at: miqro@capitainer.com.