My dentist also recommended using drs. data testing kits as well as the ones from metametrix clinical laboratory. If you have a dr. who is willing to register with them, they will send the kit to you. My chiropractor is getting the 24 hour urine test that measures heavy metals, including mercury. We are hoping to see mercury being excreted once I take a chelating agent. I also know that Genova diagnostics makes these tests as well but I am not sure of their reputation as compared to the other two labs.