Mike, unfortunately, doctors like to use HUGE amounts of DMSA for a challenge test. They have a formula they use (so many mg per kg of body weight). This would be like 10 to 20 times what you're taking, all in one HUGE dose. This is dangerous. It will most likely give you symptoms. It mobilizes lots of mercury, especially if you have any dental work. THis test will most likely yield results that don't reflect the true picture. Just my opinion, but also mentioned in Cutler's Amalgam Illness book......go for the hair test!!