Benefit of Pre - and Post - challenge Urine Heavy Metal Testing : Part 2

Measuring heavy metal levels in the urine is an accepted method for assessing the presence of a heavy metal burden in an individual. Random samples (without a flushing agent) are excellent for showing current exposures, as they reflect the level of heavy metals in the bloodstream during the hours immediately before bladder voiding. Samples taken after using a heavy metal mobilizing agent are a reflection of total body burden. Part 1 reviewed the benefits of doing pre-flush (baseline) testing utilizing the published Centers for Disease Control (CDC) heavy metal normal ranges for interpretation that allow the clinician to identify current exposures to lead and mercury and to identify cadmium toxicity. In part 2 the benefits of doing both preand post-challenge testing are reviewed. Information gleaned from performing both tests is unparalleled in allowing the clinician to identify which chelating agent will be most effective for the patient. If oral agents are employed, then possible absorption problems can be identified. Since none of these benefits are realized with only post-flush testing, it is recommended that clinicians do heavy metal testing both before and after a challenge with an effective and proven heavy metal mobilizing agent. The pitfalls of oral chelation in the case of malabsorption syndromes, such as gluten intolerance, are also discussed. (Altern Med Rev 2009;14(2):103-108) !e Benefit of Preand Postchallenge Urine Heavy Metal Testing: Part 2 Walter J. Crinnion, ND Introduction In part 1 of this article the benefits of doing a pre-flush, or baseline, measurement of urinary heavy metals were reviewed. New data published by the Centers for Disease Control (CDC) in their !ird Report provide clinicians with national baseline reference values for urine heavy metals.1 !ese numbers allow the clinician to identify current exposures by comparing patient results with national averages. Utilizing the CDC values for cadmium, along with information from studies published in Europe and Japan, also reveals cadmium toxicity with a baseline urine test. !is is vitally important because cadmium toxicity has serious health implications and there are no published values that allow it to be identified after the use of a challenge agent – calcium ethylenediaminetetraacetic acid (Ca EDTA), dimercaptosuccinic acid (DMSA), or 2,3dimercapto-1-propane sulfonic acid (DMPS). When an unchallenged (pre-flush) test is followed by a challenge (post-flush) test using a chelating agent (DMSA, DMPS, Ca EDTA, or a combination), more pertinent information can be acquired than is available if only post-flush testing is done. !is article focuses on the potential for this pair of tests to help the clinician identify the best heavy metal mobilizing agent for the patient, including the method of delivery – intravenous (IV) or oral. In order to best accomplish this task, the clinician needs to know the information in the pre-flush/baseline urine heavy metal test, as well as the heavy metal exposure history of the patient. By Walter Crinnion, ND – 1982 graduate of Bastyr University; private practice since 1982 with a special focus on treating chronic diseases caused by environmental toxic burden; conducts post-graduate seminars in environmental medicine; Professor and Chair of Environmental Medicine, Southwest College of Naturopathic Medicine. E-mail: [email protected]