ACMT Recommends Against Use of Post-Chelator Challenge Urinary Metal Testing

Abstract

Metals are ubiquitous in the environment and human populations are constantly exposed [1-4]. Detectable levels of lead, mercury, and other metals are found in blood and urine of individuals who have no clinical signs or symptoms of toxicity and thus no indication for intervention. Reference values suggest normal body burdens of these metals [1-5]. Urine testing for various metals, in an appropriate clinical context, using proper and validated methods, is an accepted medical practice. Post-chelator challenge (a.k.a. post-provocation, or provoked) is the practice of collecting specimens immediately or within 48 h of administering a chelating agent. Postchelator challenge is subject to misinterpretation and misapplication and may result in unnecessary, costly, and sometimes harmful treatment. The American College of Medical Toxicology reaffirms that post-chelator metal testing (1) has not been scientifically validated, (2) has no demonstrated benefit, and (3) may be harmful when applied in the assessment and treatment of patients in whom there is concern for metal exposure or poisoning. Evidence-Based Urine Testing for Metals In current evidence-based medical practice, urinary testing is commonly used for biomonitoring and exposure assessment for metals such as arsenic and inorganic mercury. Some