How do you decide what biological samples to use for element analysis? Can results be compared to scientific literature, or do they have clinical significance? Is it possible for values to be elevated or low in one sample type and normal in another? Do test results indicate recent intake, body burden, acute toxicity, chronic toxicity, deficiency, or homeostatic regulation?
These are just some of the questions facing a testing laboratory when they want to develop and validate essential and toxic element profiles that will provide clinically meaningful results.
Most element panels commercially available today consist of 20-30 elements analysed using a single sample type (most commonly urine or serum). It may seem like a reasonable one-stop shop for element analysis, but this is not the case!
Each element is unique in the way it is excreted, when it is excreted, and how results should be interpreted. The problem with testing a single sample type is that results may be meaningful for one element and meaningless for another. Our laboratory (ZRT) Laboratory prides itself in producing results with meaning, so instead of creating large element panels using a single sample type, we broke our element profiles up to test key toxic and essential elements in what we believe is the most clinically significant sample type.
Benefits of Heavy Metals Test
The benefits of heavy metals testing include:
- Detection of Toxic Exposure: Heavy metals testing can identify and quantify the levels of toxic heavy metals in the body, such as, mercury, cadmium, arsenic, and others. This information helps individuals become aware of their exposure and potential health risks associated with heavy metal toxicity.
- Early Identification of Health Issues: Elevated levels of heavy metals in the body can contribute to a range of health issues. By detecting and monitoring heavy metal levels, individuals can identify potential underlying causes of symptoms or chronic conditions and take appropriate action for early intervention.
- Personalized Treatment and Prevention: Heavy metals testing provides valuable information that can guide personalized treatment plans. If elevated levels are found, healthcare professionals can develop targeted strategies to reduce heavy metal exposure, promote detoxification, and support overall health and well-being.
- Environmental and Occupational Safety: For individuals working in industries with potential heavy metal exposure or living in areas with environmental pollution, heavy metals testing can help monitor their exposure levels and encourage proactive measures to minimize risk. This includes implementing safety protocols, using protective equipment, or considering environmental remediation.
- Identification of Dietary Sources: Heavy metals can also be present in certain foods, especially fish, seafood, and some agricultural products. Testing can help individuals identify potential dietary sources of heavy metals and make informed decisions about their food choices and cooking methods.
- Monitoring Treatment Effectiveness: Heavy metals testing allows individuals who are undergoing treatments or interventions for heavy metal detoxification to monitor the effectiveness of their therapies. By periodically retesting, they can track their progress and adjust their treatment plans accordingly.
- Peace of Mind and Empowerment: For individuals who suspect heavy metal exposure or are concerned about potential health risks, heavy metals testing can provide peace of mind by either confirming the absence of significant heavy metal levels or identifying areas of concern that can be addressed proactively. This empowers individuals to take control of their health and make informed decisions regarding their well-being.
Although our test result report is easy to understand, we believe It's important to note that heavy metals testing should be conducted under the guidance of a healthcare professional who can interpret the results and provide appropriate recommendations based on individual circumstances.
What do we test, and in which sample type?
Dried Urine Spot (DUS) – Iodine, Bromine, Selenium, Arsenic, Cadmium, and Mercury (plus Creatinine to correct for urine dilution)
Dried Blood Spot (DBS) – Zinc, Copper, Zinc/Copper Ratio, Magnesium, Selenium, Cadmium, and Mercury
Taking each element in turn, here's the rationale for the choice of sample type.
Iodine
Urine is the best indicator of recent dietary iodine intake, as >90% is excreted in the urine. Nearly all iodine-related studies published by major health organisations and independent research groups have used urine iodine to determine deficiency and excess in populations and recent intake in individuals. Serum iodine is sometimes used in hospitals as a quick screen to detect acute exposure, but this is uncommon.
Bromine
Urine is the best indicator of recent dietary bromine intake, as the majority is excreted in the urine.
Selenium
Urine is the best indicator of recent dietary selenium intake, as 50-70% is excreted in the urine. Both whole blood and serum indicate current body selenium status, but whole blood is believed to reflect long-term intake better than serum. The concentration of selenium in serum is about 80% of what you find in whole blood.
Arsenic
Urinary arsenic is the best indicator of recent dietary intake, as 80% is excreted in urine after three days. Serum and whole blood are poor indicators of recent dietary intake or body status for arsenic as it is cleared rapidly within a couple of hours. Serum and blood should only be used to detect very recent or extremely high levels of exposure.
Cadmium
Urinary cadmium is the best indicator of long-term exposure to this toxic element. Cadmium is concentrated in the kidneys, and urinary levels represent cumulative cadmium exposure over the long term (it has a 30-year half-life). Whole blood cadmium levels reflect recent exposure within the last 50 days. Only about 0.01-0.02% of the total body cadmium burden is excreted every day because it accumulates primarily in the kidneys. The serum is a poor indicator of exposure because cadmium in the bloodstream binds to red blood cells, with erythrocyte concentrations 20 times higher than serum.
Mercury
Urinary mercury is the best indicator of inorganic and elemental mercury exposure and kidney burden. Whole blood is the best indicator of organic (methyl or ethyl) mercury exposure, with 70-95% bound to haemoglobin in red blood cells and a half-life of around 50 days. Serum should not be used for mercury analysis.
Zinc and Copper
Whole blood or serum can be used to assess zinc and copper. Zinc and copper are functional antagonists; therefore, the zinc/copper ratio should be determined, especially in cases where values of both border high and low normal ranges. Urinary zinc levels reflect recent intake, but studies have not been able to correlate urinary zinc to tissue concentrations. In normal people, less than 3% of copper intake is excreted in the urine. Whole blood copper levels correlate better to symptoms of copper toxicity than serum, while whole blood zinc levels may better reflect intracellular and long-term zinc status than serum.
Magnesium
There is no simple laboratory test to indicate total body Mg status in humans. Less than 1% of body magnesium is found in blood, with approximately 0.3% in serum. Urinary magnesium reflects recent dietary intake and intestinal absorption but is not commonly measured. Serum magnesium is commonly tested, but there is little correlation to total body magnesium or concentrations in specific tissues. Serum magnesium levels are kept under tight homeostatic control and are usually normal even when there is a nutritional magnesium deficiency because serum levels are raised at the expense of intracellular stores. Whole blood magnesium contains a high concentration of magnesium ions, which are essential for many metabolic processes and better reflect long-term body status.
Examples
- A patient regularly eats mercury-contaminated fish. Testing would potentially show low urinary and serum mercury, while whole blood tests would be high for mercury. This is because a majority of the mercury in fish tissue is methylmercury, which can only be detected in whole blood samples.
- A patient continuously drinks water contaminated with arsenic from a well. Testing would potentially show low whole blood and serum arsenic and high urinary arsenic. This is because arsenic is cleared rapidly in blood but is excreted over multiple days in urine.
- A patient ceased smoking cigarettes (a high source of cadmium) 6 months ago but was a habitual smoker for 20 years. Whole blood and serum would potentially show low cadmium levels, while urine tests are high for cadmium. This is because whole blood represents recent cadmium intake, and serum is a poor indicator of cadmium burden, while urine indicates long-term cadmium exposure.
As you can see, proper sample type matters when testing toxic and essential elements. In certain cases, testing two sample types will provide a better picture of total exposure.
Why Test Both Blood & Urine?
Heavy metals and essential elements affect different systems of the body, so it makes sense that they can’t all be measured in the same body fluid.
ZRT tests using the most scientifically appropriate medium – either urine or dried blood spot – for our elements profiles.
For example, urinary cadmium is the best measure of accumulated exposure, while blood spot assesses only recent exposure. Blood is the only appropriate medium to assess magnesium exposure, and urine is the only appropriate medium for arsenic.
Dried Urine: ZRT’s dried urine method offers a discreet, at-home testing alternative and eliminates the hassles of all-day jug urine collection. Patients collect urine on a filter strip twice during the day. Dried strips are shelf-stable for 30 days and easy to mail back to the lab for analysis.
Dried Blood Spot: Allows testers to collect samples in the privacy of their own homes; it is simple and nearly painless, avoiding a trip to the phlebotomist.
