Take any heavy metal tests with a truckload of salt. They are not known for being completely reliable. There are quite a few people out there who have a history of heavy metal exposure and obvious heavy metal symptoms but had their tests come back negative. There are more than a few people who've tested negative, chelated anyway and felt better. God knows how many other people have gone on feeling sick with no relief because "the tests confirmed that they don't have a heavy metal problem."