Mercury for Occupational Monitoring, Urine
Screening potentially exposed workers for mercury toxicity in settings where a 24-hour collection is problematic
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Mercury (Hg), a well-known toxin, is essentially nontoxic in its elemental form. However, once it is chemically modified to the ionized, inorganic species, Hg(++), it becomes toxic. Further bioconversion to an alkyl Hg, such as methyl Hg (CHHg[+]), yields a species of Hg that is highly selective for lipid-rich tissue, such as the myelin sheath, and is very toxic.
Industrial exposure is a major source of Hg intoxication.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
Urinary mercury (Hg) is the most reliable way to assess exposure to inorganic Hg, but the correlation between the levels of excretion in the urine and clinical symptoms is poor.
The reference interval corresponds to the Occupational Safety and Health Administration (OSHA) guideline for Hg exposure.
The ordering physician will be contacted regarding any result exceeding OSHA thresholds to determine the level of workplace exposure and follow-up action.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
Nitric acid should not be added to the collection. This test is intended for use as a screening tool for occupational monitoring. It is not a replacement of HMSU / Heavy Metals Screen, 24 Hour, Urine.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Lee R, Middleton D, Caldwell K, et al. A review of events that expose children to elemental mercury in the United States. Environ Health Perspect 2009 Jun;117(6):871-878
2. Bjorkman L, Lundekvam BF, Laegreid T, et al: Mercury in human brain, blood, muscle and toenails in relation to exposure: an autopsy study. Environ Health 2007 Oct 11;6:30