Re: How do you know if you have mercury toxicity??

There is no one definitive test for mercury body burden or mercury toxicity. There are many tests for various purposes that are useful. If you have several Amalgam fillings or metal crowns over amalgam, you can be sure that you have high exposure and body burden, based on millions of past tests by medical labs. http://www.home.earthlink.net/~berniew1/damspr1.html
A hair element test is useful to determine other toxic metal exposures and essential mineral imbalances, and can be useful for mercury- though those with the most mercury toxicity problems are likely to show very low mercury levels since such people are poor excreters of mercury and the mercury is locked up in cells of the major body organs like the brain,liver, kidneys, heart, etc. Urine tests are useful for an indication of body burden mostly only after taking a chelator like DMPS or DMSA, but one needs to be very careful in doing such chemical chelation to not overburden the body by releasing more mercury than the body can deal with. Different people can be affected by different levels depending on their health status and susceptability. Anytime one does chelation or doesn dental work involving Amalgam its important to support the body with essential minerals, antioxidants, etc.
There are other tests for specific purposes such as immune reactivity(a major factor in mercury toxicity) or metabolic blockages(fractionated porphyrin test) or etc. For more details on tests, see the DAMS research page at: http://www.home.earthlink.net/~berniew1/indexd.html