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Determination of silver exposure
The bacteriostatic properties of silver have long been recognized. In the 19th century, silver nitrate was used to treat gonorrheal ophthalmia in the newborn. Current medical uses of silver-containing compounds include sulfadiazine ointment for burn patients and some nasal decongestants. Silver-coated sutures and catheters have shown some effectiveness against a broad range of bacteria. Colloidal silver is contained in various over-the-counter preparations sold in health food stores.
Environmental silver exposure can be the result of manufacture of silver nitrates as germicides, antiseptics, caustics, and analytical reagents; and for use in photography, mirrors, plating, inks, dyes, and porcelain. Additionally, sources of exposure include manufacture of silver salts as catalysts in oxidation-reduction and polymerization reactions; in chemical synthesis, in glass manufacture, in silver plating, as laboratory reagents, and in medicinal compounds.
Silver is not an essential constituent of the human body. Silver metabolism in humans has been inadequately studied and little reliable data is available. Some individuals seem to absorb silver selectively. Silver deposits in many organs, including the subepithelium of skin and mucous membranes producing a syndrome called argyria (greying of the skin). Argyria is associated with growth retardation, hemopoiesis, cardiac enlargement, degeneration of the liver, and destruction of renal tubules.
A finding of silver >1,000 ng/mL is indicative of acute silver exposure. Argyria occurs when silver levels are >2,000 ng/mL. No link between moderately elevated silver serum levels and symptoms has been reported in peer-reviewed medical literature.
Urine silver analysis is not an acceptable alternative to this test; studies have demonstrated silver is rapidly lost from urine specimens under all routine preservation conditions.
High concentrations of gadolinium and iodine are known to interfere with most metals tests. If gadolinium- or iodine-containing contrast media has been administered, a specimen cannot be collected for 96 hours.
1. Leon-Villapalos J, Jeschke MG, Herndon DN. Topical management of facial burns. Burns 2008;34:903-911
2. Lansdown AB. Critical Observations on the Neurotoxicity of Silver. Critical Reviews in Toxicology 2007;37:237–250