Here is some information about hair testing mercury

http://home.earthlink.net/~moriam/HOW_TO_hair_test.html

Its not very clear on that page, but basically, if there are so many minerals out of the normal range, there is a high probability of mercury poisoning, since mercury is the most common poison known to derange the bodies mineral transport system.

There is a group on yahoo, frequent dose chelation, that will help you interpret hair tests for free if you post them. The most common lab used is doctors data.

My hair test and another person I know both clearly showed the patterns associated with mercury toxicity, though I already knew mercury was the problem in both of those cases, mine also showed very high levels of lead, cadmium, and uranium as well. Most often, the only time hair tests will show high hair mercury is when you have been exposed to methyl mercury (ie: fish). My mercury level on my hair test was as low as could be, though I am clearly mercury poisoned based on symptoms and reactions to ALA.