According to the New York State Heavy Metals Registry, the reportable levels of mercury exposure for individuals at a high risk are at or above 5 ng/ml (nanograms/milliliters) in the blood, and at or above 20 ng/ml in urine. The urine test is the best way to measure for exposure to metallic mercury. The mercury levels in the body (which can be done in several laboratory tests), measures the level of exposure of mercury in all forms.

Besides testing for mercury exposure in individuals, environmental testing can be done with an apparatus called "a mercury vapor analyzer". This apparatus measures the levels of mercury in the air (its vapors are invisible and odorless), which are usually done indoors. The process of this measurement takes only a few minutes and the results are immediate.

What are the Alternatives?

 

Source:

Metallic Mercur:y Exposure: A Guide for Health-Care Providers. The City of New York: Department of Health.