There are many ways to treat heavy metal toxicity, including mercury. Cilantro & chlorella are lab tested as effective in removing mercury. Kombucha helps some people. Activated charcoal is something to resesarch also.
Most doctors are going to pooh pooh heavy metal testing & how many of them have had a single course in it? Of course they can learn on their own & if they do, wonderful. But I think that would not be the norm. At all.