Provoked Urine Tests for Heavy Metals: What Toxicology Research Found

Table of Contents

1. What a Provoked Urine Test Is
2. Earlier Challenge Tests and What Became of Them
3. Results in People With and Without Known Exposure
4. Recent Exposure Versus Exposure Years Ago
5. Clinic and Symptom Studies
6. The Reference Range Problem
7. How Practitioners Who Use the Test Describe Its Value
8. Reported Harms From the Chelating Drugs
9. The Reported Deaths, as Published
10. What Societies, Laboratories and Regulators Have Stated
11. Other Ways Body Burden Is Measured
12. What Is Still Not Known
13. Key Research Papers
14. Connections
15. Featured Videos

What a Provoked Urine Test Is

The test goes by several names: urine mobilization test, challenge test, post-chelator test and provoked urine test. In each case a chelating agent is given first and urine is collected afterward. The word chelate comes from the Greek word for a claw, because the drug grips a metal atom at two or more points so that the kidney can carry it out.

Three drugs are the ones most often named in this literature:

• Dimercaptosuccinic acid (DMSA), also called succimer. The US Food and Drug Administration approved it in 1990 for lead intoxication. It also binds mercury.
• Dimercaptopropane sulfonate (DMPS), approved in Europe but not in the United States, where it can be obtained through compounding pharmacies.
• Ethylenediaminetetraacetic acid (EDTA), which comes in two different medicinal forms, edetate calcium disodium and edetate disodium. The difference between them turned out to matter a great deal, as the section on deaths describes.

A 2013 review in the Journal of Medical Toxicology reported that there is no standard, validated version of the test. The drugs are given by mouth, rectally, by intramuscular injection or by infusion, at inconsistent doses, and urine collection ranges from a single spot sample to a full 24 hours. A skin-applied form of dimercaptopropane sulfonate has also been advertised. When eight adult volunteers tried it, none had detectable drug in the urine or any rise in urine mercury, while one control subject who swallowed 250 milligrams did show both. The authors concluded that the skin form is not absorbed.

This differs from an ordinary urine metal test, which involves no drug beforehand. The American College of Medical Toxicology describes ordinary testing, in the right clinical setting and with validated methods, as accepted medical practice. It defines the provoked version as collecting specimens immediately or within 48 hours of giving a chelating agent.

The US National Center for Health Statistics figures quoted in a 2013 review counted about 66,000 adults receiving some form of chelation in 2002, and 111,000 adults plus an estimated 72,000 children in 2007. Those figures cover chelation in general, not provoked tests specifically. No count of provoked tests appeared in any source read for this page.

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Earlier Challenge Tests and What Became of Them

The idea is more than 50 years old, and the 2013 review traces it through three older tests.

• Deferoxamine for iron. Introduced in the early 1960s to diagnose iron storage disease. In rabbits, urine iron rose 16-fold in animals loaded with iron and fivefold in normal animals. The test became standard for acute iron toxicity, then proved poor at separating toxic from non-toxic patients and was ultimately recommended for abandonment.
• Edetate calcium disodium for lead. Developed in the early 1960s. Lead-poisoned children excreted more lead than controls, but all children showed a rise. By the 1980s it was widely used, and the US Centers for Disease Control and Prevention recommended it for deciding which patients would respond to chelation. It was later abandoned, for reasons the review lists as safety concerns, difficulty performing it in children, and data showing that the lead came initially mainly from bone.
• Penicillamine for copper. Still sometimes used as an aid in diagnosing Wilson's disease. In a 2010 study of 40 patients and 58 controls described in the review, urine copper rose in both groups and the difference between them disappeared after the challenge. The review calls this the one possible exception among challenge tests accepted in conventional medicine today.

In each of the three, the drug raised urine metal in people with no excess of that metal. The same finding runs through the mercury and lead studies below.

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Results in People With and Without Known Exposure

Most of the human data concern mercury. Doses appear as the studies gave them.

• Dental fillings, 1992. Volunteers were given 300 milligrams of dimercaptopropane sulfonate by mouth. Mean urine mercury over 9 hours went from 0.70 to 17.2 micrograms in people with amalgam fillings and from 0.27 to 5.1 micrograms in those without. The authors read this as showing that the drug makes urine mercury a more reliable measure of exposure.
• Dental workers, 1995. Using the same dose, 6-hour urine mercury went from 4.84 to 424.0 micrograms in 10 dental technicians, from 3.28 to 162.0 in 5 dentists, and from 0.783 to 27.3 in 13 people outside dentistry. The authors called the test useful for monitoring dental personnel for mercury vapor exposure.
• A mercury skin lotion, 1996. Six-hour urine mercury rose from 113 to 5,037 micrograms in 11 workers who made the lotion, from 16.2 to 1,410 in 8 users, and from 0.49 to 18.4 in 9 controls. Those are 45-, 87- and 38-fold rises.
• Industrial workers, 1991. The 24-hour rise after 300 milligrams of dimercaptopropane sulfonate was tenfold in 10 workers, 5.9-fold in 8 dentists, 5.3-fold in 18 controls and 3.8-fold in 5 people with no amalgam fillings.
• Workers and dentists, 2000. Urine mercury over the 48 hours after the first of two doses reached 1,513 micrograms in 43 chloralkali workers, 132.6 in 12 dentists and 3.78 in 20 non-exposed people.
• Fish eaters, 2009. Healthy physicians (24 completed, 2 later excluded) took 30 milligrams per kilogram of dimercaptosuccinic acid. There was no baseline difference by fish intake. Urine mercury rose in every group, more in fish eaters, and the prechelation blood mercury was the best predictor of the rise. The authors concluded that a simple rise over baseline is not a reliable sign of mercury poisoning.
• A 2026 lead series. Among 63 patients given intravenous pentetate calcium trisodium for suspected gadolinium-related symptoms, median urine lead went from 0.283 to 3.22 micrograms per 24 hours, a median 11.8-fold rise. The authors stated that this does not establish lead poisoning, a fall in total body lead, or symptom improvement.

So at the level of groups with large or current exposure, the post-drug numbers do differ. The 2013 review argued that the difficulty lies at the level of the individual. In the 1995 dental study as it reports the ranges, controls rose anywhere from 14-fold to 132-fold and dental technicians from 11-fold to 335-fold. In a 2004 study of healthy volunteers, the highest rise (27-fold) came in someone with six amalgam surfaces and the lowest (onefold) in someone with 36. The review's conclusions were that unprovoked levels are higher in currently exposed groups, that the drugs raise urine mercury in everyone including people with no known exposure, and that the fold increase overlaps so much that it cannot be predicted from an exposure history.

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Recent Exposure Versus Exposure Years Ago

The main use claimed for the test is revealing old metal that an ordinary test misses. Two studies addressed this directly for mercury.

The 1991 study above found close associations between mobilized mercury and the mercury already in plasma and urine before the drug, but none with the duration of occupational exposure. Its authors concluded that the mobilized mercury is mainly an index of recent exposure and is not significantly affected by slow body pools or long-term exposure.

A 2001 study followed 119 former chloralkali plant workers with detailed exposure histories and 101 unexposed controls. All collected 24-hour urine before and after two doses of 10 milligrams per kilogram of dimercaptosuccinic acid. Average excretion was 4.3 micrograms per 24 hours before and 7.8 after. Past occupational exposure was not associated with urine mercury either before or after the drug, and neither was the number of amalgam surfaces. The authors thought the several years since exposure ended was the likeliest explanation, and concluded that the challenge is not useful as a marker of past mercury exposure.

For lead, a 2006 study of 80 Belgian adults (40 controls and 40 lead-exposed, 1 gram of dimercaptosuccinic acid by mouth) found that urine lead after the drug climbed steeply and scattered widely once blood lead passed 300 micrograms per liter, and judged its diagnostic value likely to be contributive above that level. A study of 802 Korean lead workers and 135 controls found that blood lead accounted for the largest share of variation in chelatable lead, which ranged from 4.8 to 2,102.9 micrograms.

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Clinic and Symptom Studies

The most direct test of the practice is whether a provoked result points to people who are actually poisoned.

• The prospective clinic study, 2022. The Toxicology Investigators Consortium registry followed patients who arrived at toxicology clinics with provoked results already in hand. Of 106 such cases, 74 met the criteria. A board-certified medical toxicologist judged 15 of them likely related to a toxic exposure and only three related to heavy metals, giving a positive predictive value of 4.3%. The authors wrote that no earlier prospective study of the question existed, and concluded that the test "should not be performed."
• Symptoms attributed to amalgam, 2000. Intravenous dimercaptopropane sulfonate (2 milligrams per kilogram) was given to 19 healthy people who never had amalgam, 21 healthy people with amalgam, 20 patients who attributed symptoms to amalgam, and 20 who had removed fillings for that reason. Total excretion was similar in the symptomatic and healthy groups with amalgam. Fillings predicted the result, about threefold; symptoms did not.
• A healthy-volunteer test, 2004. Self-reported healthy people given 30 milligrams per kilogram of dimercaptosuccinic acid had mercury-to-creatinine ratios similar to those previously reported in people with symptoms attributed to mercury. The authors stated that the test may lead to misleading diagnostic advice.
• Children with autism, 2007. In a pilot study, 15 children with autism and 4 typically developing children completed a baseline and a provoked 24-hour collection. Three of the autistic children excreted one metal in greater quantity after the drug. Two of those were very close to the limit of detection, and the third was within normal on retesting after fish was removed from the diet for over a month. The authors put the proportion with an excess chelatable burden at zero (confidence interval 0–22%). A 2020 pediatric review describes studies comparing provoked results in cases with unprovoked results in controls as fundamentally flawed.
• Placebo-controlled treatment trials. Twenty people attributing symptoms to amalgam received 20 milligrams per kilogram of dimercaptosuccinic acid or placebo for 14 days in a 1994 trial. Urine mercury rose 65% on average and was back at the starting level three months later. Symptoms and mood showed no treatment effect apart from a decrease in fatigue-inertia, which did not track the mercury measures. In a double-blind 1997 trial among 50 patients, most distress measures improved considerably, with no difference between the drug (30 milligrams per kilogram daily for five days) and placebo.

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The Reference Range Problem

A laboratory value means little without a range to compare it to. Ordinary ranges for urine metals come from people who took no chelator. The American College of Medical Toxicology states that acceptable normal values for post-challenge urine have not been established, that post-chelator results cannot be compared to normal reference values, and that efforts to convert a provoked result back into an unprovoked one are unproven. It adds that the conversion rests on a small 1991 study that was never subsequently validated.

The 2013 review gathered the post-drug mercury values reported for healthy control and amalgam-only groups. It reported that all of the means were higher than expected without a chelator and higher than typical reference ranges, and that a true reference range could not be derived because the studies differed in dose, drug, collection time and units. Its sample values include 5 micrograms over 9 hours in people with no amalgam and 8 micrograms per 24 hours in the 101 controls of the 2001 study.

Two groups have proposed figures of their own. The authors of the 2001 study described their numbers as normative values for mercury before and after the drug. The authors of the 2006 Belgian study proposed an upper limit of 22 micrograms of lead per 4 hours for Belgian reference individuals. Neither has become a general standard in the sources read here.

How a Short Collection and Creatinine Can Move the Number

Urine results are often divided by creatinine to adjust for how dilute the urine is. The 2013 review argued that this misleads when applied to a short collection right after the drug, because most of the metal appears early. Its simplified example: a person excretes 4 micrograms of mercury and 1 gram of creatinine per day. If the drug triples mercury excretion for the first 6 hours only, the full-day figure becomes 6 micrograms per gram of creatinine, but the 6-hour sample reports 12. Same person, same dose, double the number. The 1991 study found that 59% of the mercury excreted over 24 hours appeared in the first 6.

The review also describes how a sample report looks: out-of-range values on a yellow or red background, with the fact that the test was provoked stated in fine print at the end.

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How Practitioners Who Use the Test Describe Its Value

The following are the views of clinicians and writers who use or defend the test, as they published them.

• A complete picture needs both samples. A two-part 2009 series in an alternative medicine journal describes a random urine sample as showing current exposure and a post-chelator sample as a reflection of total body burden. Its author writes that testing before and after a challenge identifies which chelating agent works best for a patient, and whether oral agents are being absorbed, and recommends that clinicians do both.
• "Normal" is not healthy. A 2015 editorial in an integrative medicine journal argues that reference populations are themselves burdened with toxins and chronic disease, so that a rise in "healthy" people does not count against the test. It states that blood reflects current exposure rather than body load, and that people vary widely in their ability to clear toxins.
• Criticism of the negative studies. The same editorial argues that the 2001 chloralkali study used a control community that may itself have been exposed, that the 1994 trial left amalgam fillings in place, that creatinine correction is standard practice for adjusting to urine volume, and that the 2009 fish study in fact showed the drug separating fish eaters by intake better than unprovoked urine.
• The case for the test. That editorial reports the largest data set, 2,137 people in a wellness program, in which challenge urine mercury was 6.3 micrograms per gram of creatinine with amalgam and 2.75 without, and it cites animal work relating post-chelator mercury to exposure. The published paper from that program reports an average unprovoked difference of 0.55 micrograms per gram of creatinine and states that results after the two chelators were also significantly higher with amalgam.
• Monitoring. The editorial's author tentatively concludes that the test correlates with mercury body load "to an unclear degree," writes of being confident in using it to monitor response to intervention, and states that its reliability as a diagnostic tool is not clear but that it appears to be "the best we currently have available." The author lists unknown optimal doses and no standard for toxic versus safe levels as open problems, and describes doses of 500 milligrams of dimercaptosuccinic acid as extremely unlikely to cause problems.
• Screening of healthy people. A 2020 cohort report describes 15 healthy, asymptomatic patients whose provocative urine lead was treated as a marker of total body lead during routine health screening. After an average of 14 calcium ethylenediaminetetraacetic acid infusions over 24 months, the measured lead fell by an average of 39.16%. There was no control group described in the abstract.

The 2013 toxicology review describes one website stating that any rise after a chelator counts as significant, and advocates advising a search of a patient's history, as far back as maternal exposure before conception, until a source of metal is identified.

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Reported Harms From the Chelating Drugs

Harm can come from the test dose itself, or from treatment that a test result leads to.

Reactions to a Test Dose

• In the 2004 volunteer study, the 2013 review reports, enrolment stopped after one volunteer developed vomiting, chest tightness and a hive-like rash six minutes after dimercaptosuccinic acid. The study abstract describes it as a serious reaction.
• In the 1992 dental study, one subject vomited and another developed a rash a week after treatment, according to the same review.
• Foul-smelling urine and nausea were also reported by volunteers in the 2004 study.

Reactions During Longer Treatment

• Three of the 20 subjects in the 1994 amalgam trial had hypersensitive reactions, probably specific to dimercaptosuccinic acid.
• An 11-year-old boy developed Stevens-Johnson syndrome, a serious skin and mucous membrane reaction, after two weeks of oral dimercaptopropane sulfonate for chronic mercury vapor exposure. It resolved gradually after the drug was stopped.
• A 2013 review reports mild liver enzyme elevations and allergic reactions with dimercaptosuccinic acid.

Loss of Essential Minerals

Chelators do not bind only the toxic metals. After 1 gram of dimercaptosuccinic acid in the Belgian study, copper and zinc excretion rose by up to 91-fold and 33-fold, though no side effects were reported. The American College of Medical Toxicology lists increased loss of iron, copper and zinc with edetate calcium disodium, and of zinc, magnesium and manganese with pentetate. It also describes dimercaptosuccinic acid and dimercaptopropane sulfonate as able to redistribute metals such as mercury between organs.

What Treatment Did in the Large Trial

The largest controlled evidence on chelation in children concerns real lead exposure. In a trial of 780 children aged 12 to 33 months with blood lead of 20 to 44 micrograms per deciliter, up to three 26-day courses of dimercaptosuccinic acid lowered blood lead by 4.5 micrograms per deciliter over six months. At 36 months the children given the drug had an IQ score 1 point lower than those on placebo and slightly worse parent-rated behavior, with slightly better neuropsychological scores. None of these differences reached statistical significance. The authors concluded that chelation was not indicated at these blood lead levels. Scalp rashes were more common with the drug (3.5% versus 1.3%), and an unexpected excess of trauma was reported that the authors said needed confirmation. Height change over 34 months was 0.43 centimeters less with the drug. A 2013 discussion of the trial notes that blood lead could not be told apart between treated and untreated children at one year.

In rats with no prior lead exposure, dimercaptosuccinic acid produced lasting cognitive and emotional dysfunction comparable in size to that from the higher lead exposure regimen. In lead-exposed rats, the same drug improved learning, attention and arousal regulation.

Chelation for Autism

The 2015 Cochrane review, which included a single trial with methodological limitations, found no clinical trial evidence that chelation is an effective treatment for autism. Children who qualified as "high excreters" after a three-day course moved on to repeated dimercaptosuccinic acid or placebo, and no effect on symptoms was found. Citing prior reports of low blood calcium, kidney impairment and death, the reviewers concluded that risks outweighed proven benefits. A 2013 commentary states that results are often falsely elevated when post-chelator urine is compared with ranges for non-chelated urine, and that unnecessary chelation is expensive and can cause significant acute adverse effects.

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The Reported Deaths, as Published

One point about the evidence comes first. The published summaries describe deaths during chelation given as treatment. None of the summaries read for this page states that a provoked urine test came first in these particular cases. The link to testing made by the American College of Medical Toxicology is indirect: provoked results lead to chelation, and chelation has been fatal.

• Centers for Disease Control and Prevention, 2006. A weekly report titled for Texas, Pennsylvania and Oregon described three deaths from 2003 to 2005 associated with chelation-related low blood calcium that resulted in cardiac arrest.
• A paper in Pediatrics, 2006. It described three deaths from the same years, reported to the Centers for Disease Control and Prevention, as cardiac arrest caused by low blood calcium during chelation therapy. Two were children, both treated with edetate disodium. The adult case was still under investigation at the time of writing. The authors stated that no previous deaths from low blood calcium during chelation had been reported.
• A pediatric case report, 2008. A five-year-old boy with autism went into cardiac arrest during his third chelation treatment in a physician's office. Only after his death was it found that he had been given edetate disodium rather than edetate calcium disodium, causing profound low blood calcium. The abstract does not say whether this child is one of the two in the reports above, so the counts cannot simply be added together.
• The adult case, as described in a 2013 review. A 53-year-old woman received 700 milligrams of ethylenediaminetetraacetic acid intravenously over 10 to 15 minutes in a naturopathic practitioner's clinic, with the intention of removing heavy metals. She became unconscious and had a cardiac arrest 10 to 15 minutes later. Her ionized calcium remained critically low at 3.8 milligrams per deciliter (normal 4.5 to 5.3) despite calcium given during resuscitation, and she died.

The difference between the two forms is chemical. The form with calcium already attached does not bind more calcium from the blood. The form without it does. The names differ by a single word, and the 2013 review notes how easily they are confused. The American College of Medical Toxicology also lists deaths and aluminum brain injury with deferoxamine in people on dialysis, and states that clearing a chelated metal through the kidney may increase the kidney toxicity of certain metals, such as cadmium.

The Centers for Disease Control and Prevention had recommended in 1991 that only edetate calcium disodium be used in children, according to the 2008 case report.

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What Societies, Laboratories and Regulators Have Stated

Medical Societies

The American College of Medical Toxicology published its position in 2009, and it appeared in the journal record in 2010 (PMID 20354920). The full text of that older version could not be read for this page, so it is described here only through later papers that cite it. Its 2017 restatement (PMID 28726084) was read in full. It says that post-chelator metal testing has not been scientifically validated, has no demonstrated benefit, and may be harmful when applied to patients in whom there is concern for metal exposure or poisoning. It describes human studies in which the test failed to separate people with and without documented exposure, or with and without clinical findings of toxicity.

A 2020 pediatric review names the American College of Medical Toxicology, the American Academy of Clinical Toxicology and the Pediatric Environmental Health Specialty Units as expert groups that do not recommend the test. A 2026 review of heavy metal toxicity lists it as unvalidated.

Federal Agency Scientists

A 2005 paper by scientists at the Agency for Toxic Substances and Disease Registry addressed the inappropriate use of chelating agents in diagnosing mercury poisoning, and reported that controlled studies showing chelation improves outcome were lacking. The 2013 provoked-testing review describes authors from that agency and the Centers for Disease Control and Prevention as concluding that these tests have no place as diagnostic tools. A 2013 review adds that the agency received dozens of calls each year from people chelated before any urine sample was collected and then diagnosed with mercury poisoning. It also describes an agency health consultation in which post-chelator spot mercury values of 10 and 21 micrograms per gram of creatinine were used to justify treatment, and no source of mercury could be located.

Laboratories

No statement from a laboratory organization turned up in the sources read for this page. What the sources describe is laboratory practice. The American College of Medical Toxicology states that some laboratories and care providers apply unprovoked reference values to post-challenge results. It also says that ranges for ordinary testing come from nationally certified laboratories meeting proficiency standards. The 2020 pediatric review notes that many results, even from a certified laboratory, can only be compared with the background levels in the Centers for Disease Control and Prevention's national exposure report.

Regulators

• Edetate disodium. The 2013 review reports that it was withdrawn from the US market in 2008, in part because of the deaths, and is no longer approved by the US Food and Drug Administration.
• Dimercaptosuccinic acid. Approved for lead poisoning in children with blood lead above 45 micrograms per deciliter. Use for mercury and arsenic is not an approved indication.
• Dimercaptopropane sulfonate. Not approved in the United States. The same review quotes a 1999 Federal Register notice saying it "appears to be relatively nontoxic," and comments that this may understate the problems.
• Who can obtain them. That review reports that any licensed provider can prescribe a chelator, and that some products are available through compounding pharmacies and over the internet.

No US Food and Drug Administration statement specifically about provoked urine testing was found in the sources read for this page.

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Other Ways Body Burden Is Measured

Body burden means the metal held in the body, including stores such as bone. The sources below describe these measures and their limits.

• Blood lead. The primary marker of lead exposure. A 2005 review reports that a single measurement cannot separate low-level long-term exposure from a short high exposure, that serial measurements estimate outcomes better, and that no other marker has yet been accepted as a reliable substitute.
• Bone lead by X-ray fluorescence. A noninvasive measurement that reflects long-term exposure because lead stays in bone for a long time. A 1994 review reported that it was still largely confined to research institutions. In 802 Korean workers, tibial lead tracked age and job duration. In 543 former organolead workers, blood lead was linked to blood pressure, while chelatable lead and tibial lead were not.
• Unprovoked 24-hour urine. The American College of Medical Toxicology lists three appropriate settings: a known significant acute exposure, a suspected exposure with consistent symptoms, and occupational biomonitoring. It states that a collection after therapeutic chelation waits for a sufficient interval, such as 3 to 5 days. Chromium is named as showing no clear link between urine level and effect, and urine is not the right specimen for metal-on-metal hip implants.
• Urine mercury and speciated arsenic. The 2020 pediatric review gives urine mercury as useful for subacute elemental mercury vapor exposure with suggestive findings, and urine arsenic for possible well-water exposure with matching symptoms. In its case example, separating organic from inorganic arsenic showed that a raised total came from diet.
• Hair. The same review reports that commercial hair tests do not reliably reflect levels inside the body and cannot tell metal inside the hair from metal on its surface.

That review states the general approach as an exposure history plus clinical findings consistent with the specific metal, followed by a chosen test for that metal. The ordinary laboratory test is described on the heavy metals panel page.

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What Is Still Not Known

• The correlation with stored metal. Both sides of the argument name this gap. The 2015 editorial writes that it is not known how well challenge results correlate with actual body load. The 2013 review reports no well-designed randomized study comparing a challenge test in people with and without proven metal poisoning.
• A standard method. Drug, dose, route and collection time all still vary, so studies cannot be pooled into a reference range.
• Who was truly poisoned. The 2022 clinic study used a medical toxicologist's judgement as its standard, not a direct measure of stored metal. It included only patients who reached toxicology clinics, and only three cases were attributed to heavy metals.
• Stores seen only after a chelator. The 2005 lead review and the bone studies show that long-term lead stores are hard to measure. Whether health effects follow from stores that only a chelator reveals has not been shown in the sources here.
• Long-term effects of chelation without poisoning. The finding of lasting cognitive change comes from rats. The children's trial enrolled children with raised lead. No equivalent long-term human data in unexposed people appeared in the sources read.
• How common the test is. Chelation has been counted. Provoked testing has not, in any source read here.

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Key Research Papers

1. Weiss ST, Campleman S, Wax P, McGill W, Brent J; Toxicology Investigators Consortium. Failure of chelator-provoked urine testing results to predict heavy metal toxicity in a prospective cohort of patients referred for medical toxicology evaluation. Clin Toxicol (Phila). 2022;60(2):191-196. PubMed PMID: 34184587
2. Ruha AM. Recommendations for provoked challenge urine testing. J Med Toxicol. 2013;9(4):318-25. PubMed PMID: 24113861
3. American College of Medical Toxicology. ACMT Recommends Against Use of Post-Chelator Challenge Urinary Metal Testing. J Med Toxicol. 2017;13(4):352-354. PubMed PMID: 28726084
4. American College of Medical Toxicology. American College of Medical Toxicology position statement on post-chelator challenge urinary metal testing. J Med Toxicol. 2010;6(1):74-5. PubMed PMID: 20354920
5. Wax PM. Current use of chelation in American health care. J Med Toxicol. 2013;9(4):303-7. PubMed PMID: 24113860
6. Cohen JP, Ruha AM, Curry SC, Biswas K, Westenberger B, Ye W, Caldwell KL, Lovecchio F, Burkhart K, Samia N. Plasma and urine dimercaptopropanesulfonate concentrations after dermal application of transdermal DMPS (TD-DMPS). J Med Toxicol. 2013;9(1):9-15. PubMed PMID: 23143832
7. Aposhian HV, Bruce DC, Alter W, Dart RC, Hurlbut KM, Aposhian MM. Urinary mercury after administration of 2,3-dimercaptopropane-1-sulfonic acid: correlation with dental amalgam score. FASEB J. 1992;6(7):2472-6. PubMed PMID: 1563599
8. Gonzalez-Ramirez D, Maiorino RM, Zuniga-Charles M, Xu Z, Hurlbut KM, Junco-Munoz P, Aposhian MM, Dart RC, Diaz Gama JH, Echeverria D, et al. Sodium 2,3-dimercaptopropane-1-sulfonate challenge test for mercury in humans: II. Urinary mercury, porphyrins and neurobehavioral changes of dental workers in Monterrey, Mexico. J Pharmacol Exp Ther. 1995;272(1):264-74. PubMed PMID: 7815341
9. Maiorino RM, Gonzalez-Ramirez D, Zuniga-Charles M, Xu Z, Hurlbut KM, Aposhian MM, Dart RC, Woods JS, Ostrosky-Wegman P, Gonsebatt ME, Aposhian HV. Sodium 2,3-dimercaptopropane-1-sulfonate challenge test for mercury in humans. III. Urinary mercury after exposure to mercurous chloride. J Pharmacol Exp Ther. 1996;277(2):938-44. PubMed PMID: 8627576
10. Molin M, Schütz A, Skerfving S, Sällsten G. Mobilized mercury in subjects with varying exposure to elemental mercury vapour. Int Arch Occup Environ Health. 1991;63(3):187-92. PubMed PMID: 1917069
11. Nerudová J, Cábelková Z, Frantík E, Lukás E, Urban P, Bláha K, Pelclová D, Lebedová J, Cikrt M. Mobilization of mercury by DMPS in occupationally exposed workers and in model experiments on rats: evaluation of body burden. Int J Occup Med Environ Health. 2000;13(2):131-46. PubMed PMID: 10967843
12. Ruha AM, Curry SC, Gerkin RD, Caldwell KL, Osterloh JD, Wax PM. Urine mercury excretion following meso-dimercaptosuccinic acid challenge in fish eaters. Arch Pathol Lab Med. 2009;133(1):87-92. PubMed PMID: 19123743
13. Semelka RC, Ramalho M. Incidental Changes in Urinary Lead Excretion Following Intra-Venous Ca-DTPA Administration in Patients Treated Primarily for Gadolinium Exposure. J Xenobiot. 2026;16(4):135. PubMed PMID: 42646049
14. Archbold GP, McGuckin RM, Campbell NA. Dimercaptosuccinic acid loading test for assessing mercury burden in healthy individuals. Ann Clin Biochem. 2004;41(Pt 3):233-6. PubMed PMID: 15117439
15. Frumkin H, Manning CC, Williams PL, Sanders A, Taylor BB, Pierce M, Elon L, Hertzberg VS. Diagnostic chelation challenge with DMSA: a biomarker of long-term mercury exposure? Environ Health Perspect. 2001;109(2):167-71. PubMed PMID: 11266328
16. Hoet P, Buchet JP, Decerf L, Lavalleye B, Haufroid V, Lison D. Clinical evaluation of a lead mobilization test using the chelating agent dimercaptosuccinic acid. Clin Chem. 2006;52(1):88-96. PubMed PMID: 16239340
17. Todd AC, Lee BK, Lee GS, Ahn KD, Moshier EL, Schwartz BS. Predictors of DMSA chelatable lead, tibial lead, and blood lead in 802 Korean lead workers. Occup Environ Med. 2001;58(2):73-80. PubMed PMID: 11160984
18. Vamnes JS, Eide R, Isrenn R, Höl PJ, Gjerdet NR. Diagnostic value of a chelating agent in patients with symptoms allegedly caused by amalgam fillings. J Dent Res. 2000;79(3):868-74. PubMed PMID: 10765962
19. Soden SE, Lowry JA, Garrison CB, Wasserman GS. 24-hour provoked urine excretion test for heavy metals in children with autism and typically developing controls, a pilot study. Clin Toxicol (Phila). 2007;45(5):476-81. PubMed PMID: 17503250
20. Zajac L, Johnson SA, Hauptman M. Doc, can you test me for "toxic metals"? Challenges of testing for toxicants in patients with environmental concerns. Curr Probl Pediatr Adolesc Health Care. 2020;50(2):100762. PubMed PMID: 32115369
21. Sandborgh Englund G, Dahlqvist R, Lindelöf B, Söderman E, Jonzon B, Vesterberg O, Larsson KS. DMSA administration to patients with alleged mercury poisoning from dental amalgams: a placebo-controlled study. J Dent Res. 1994;73(3):620-8. PubMed PMID: 8163732
22. Grandjean P, Guldager B, Larsen IB, Jørgensen PJ, Holmstrup P. Placebo response in environmental disease. Chelation therapy of patients with symptoms attributed to amalgam fillings. J Occup Environ Med. 1997;39(8):707-14. PubMed PMID: 9273873
23. Crinnion WJ. The benefits of pre- and post-challenge urine heavy metal testing: Part 1. Altern Med Rev. 2009;14(1):3-8. PubMed PMID: 19364190
24. Crinnion WJ. The benefit of pre- and post-challenge urine heavy metal testing: part 2. Altern Med Rev. 2009;14(2):103-8. PubMed PMID: 19594221
25. Pizzorno J. Is Challenge Testing Valid for Assessing Body Metal Burden? Integr Med (Encinitas). 2015;14(4):8-14. PubMed PMID: 26770151
26. Dutton DJ, Fyie K, Faris P, Brunel L, Emery JH. The association between amalgam dental surfaces and urinary mercury levels in a sample of Albertans, a prevalence study. J Occup Med Toxicol. 2013;8(1):22. PubMed PMID: 23984857
27. Petteruti S. Reduction of Lead Levels in Patients Following a Long-Term, Intermittent Calcium Ethylenediaminetetraacetic Acid (EDTA)-Based Intravenous Chelation Infusions: A Prospective Experimental Cohort. Cureus. 2020;12(11):e11685. PubMed PMID: 33262921
28. Van der Linde AA, Pillen S, Gerrits GP, Bouwes Bavinck JN. Stevens-Johnson syndrome in a child with chronic mercury exposure and 2,3-dimercaptopropane-1-sulfonate (DMPS) therapy. Clin Toxicol (Phila). 2008;46(5):479-81. PubMed PMID: 18568806
29. Rogan WJ, Dietrich KN, Ware JH, Dockery DW, Salganik M, Radcliffe J, Jones RL, Ragan NB, Chisolm JJ Jr, Rhoads GG; Treatment of Lead-Exposed Children Trial Group. The effect of chelation therapy with succimer on neuropsychological development in children exposed to lead. N Engl J Med. 2001;344(19):1421-6. PubMed PMID: 11346806
30. Treatment of Lead-Exposed Children (TLC) Trial Group. Safety and efficacy of succimer in toddlers with blood lead levels of 20-44 microg/dL. Pediatr Res. 2000;48(5):593-9. PubMed PMID: 11044477
31. Peterson KE, Salganik M, Campbell C, Rhoads GG, Rubin J, Berger O, Ware JH, Rogan W. Effect of succimer on growth of preschool children with moderate blood lead levels. Environ Health Perspect. 2004;112(2):233-7. PubMed PMID: 14754579
32. McKay CA Jr. Role of chelation in the treatment of lead poisoning: discussion of the Treatment of Lead-Exposed Children Trial (TLC). J Med Toxicol. 2013;9(4):339-43. PubMed PMID: 24178899
33. Stangle DE, Smith DR, Beaudin SA, Strawderman MS, Levitsky DA, Strupp BJ. Succimer chelation improves learning, attention, and arousal regulation in lead-exposed rats but produces lasting cognitive impairment in the absence of lead exposure. Environ Health Perspect. 2007;115(2):201-9. PubMed PMID: 17384765
34. James S, Stevenson SW, Silove N, Williams K. Chelation for autism spectrum disorder (ASD). Cochrane Database Syst Rev. 2015;5(5):CD010766. PubMed PMID: 26114777
35. Brent J. Commentary on the abuse of metal chelation therapy in patients with autism spectrum disorders. J Med Toxicol. 2013;9(4):370-2. PubMed PMID: 24113859
36. Centers for Disease Control and Prevention (CDC). Deaths associated with hypocalcemia from chelation therapy--Texas, Pennsylvania, and Oregon, 2003-2005. MMWR Morb Mortal Wkly Rep. 2006;55(8):204-7. PubMed PMID: 16511441
37. Brown MJ, Willis T, Omalu B, Leiker R. Deaths resulting from hypocalcemia after administration of edetate disodium: 2003-2005. Pediatrics. 2006;118(2):e534-6. PubMed PMID: 16882789
38. Baxter AJ, Krenzelok EP. Pediatric fatality secondary to EDTA chelation. Clin Toxicol (Phila). 2008;46(10):1083-4. PubMed PMID: 18949650
39. Risher JF, Amler SN. Mercury exposure: evaluation and intervention the inappropriate use of chelating agents in the diagnosis and treatment of putative mercury poisoning. Neurotoxicology. 2005;26(4):691-9. PubMed PMID: 16009427
40. Chakif D, Furrer J. Heavy Metal Toxicity in Clinical and Environmental Health: Sources, Mechanisms, Diagnostics, and Evidence-Based Management of Mercury, Lead, Cadmium, and Arsenic. Int J Mol Sci. 2026;27(8):3513. PubMed PMID: 42074156
41. Barbosa F Jr, Tanus-Santos JE, Gerlach RF, Parsons PJ. A critical review of biomarkers used for monitoring human exposure to lead: advantages, limitations, and future needs. Environ Health Perspect. 2005;113(12):1669-74. PubMed PMID: 16330345
42. Todd AC, Chettle DR. In vivo X-ray fluorescence of lead in bone: review and current issues. Environ Health Perspect. 1994;102(2):172-7. PubMed PMID: 8033846
43. Schwartz BS, Stewart WF. Different associations of blood lead, meso 2,3-dimercaptosuccinic acid (DMSA)-chelatable lead, and tibial lead levels with blood pressure in 543 former organolead manufacturing workers. Arch Environ Health. 2000;55(2):85-92. PubMed PMID: 10821507

PubMed Topic Searches

1. Provoked urine test for metals
2. Chelation challenge and urine mercury
3. Lead mobilization test
4. Chelation, low blood calcium and death
5. Bone lead by X-ray fluorescence

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Connections

• Toxic Minerals & Heavy Metals — the parent category
• Lead Poisoning — sources, health effects and blood lead
• Mercury Toxicity — the metal most of these studies measured
• Arsenic Exposure — where organic and inorganic forms matter to a urine result
• Cadmium — another metal measured in unprovoked urine
• Heavy Metals Panel — the ordinary laboratory test
• Wilson's Disease — where a penicillamine challenge is still sometimes used
• Natural Detox Protocols — related claims about removing toxins

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