I have been recent victim of dental Amalgam poisoning. It is a real problem that seems to affect some people more than others, simply because of genetics. However, eventually everyone who has these fillings would pay the price for them, whether earlier or later on in life.
Blood tests for mercury poisoning are ineffective because mercury is stored in the tissues. You need a chelator such as DMPS or DMSA to bind to mercury and pull it out of your tissues. DMPS is given intravenously, while DMSA is an oral tablet that works just as well. However, you should not test for mercury until you have replaced all of your dental amalgams. It wouldn't make sense to do it with them in there since you would be pulling mercury from your teeth.