DDI Hair Elements or a low-dose DMSA trial
I've been doing some reading for heavy metal tests and i'm finding it very confusing. Some recommend the provocation test, whilst elsewhere I've read these give erroneous results and are not recommended.
I've also seen the urine porphyrins test mentioned. Any opinions would be most welcome.
Definitely not a challenge test; they are simply not worth the risk of a major redistribution. Unprovoked blood and stool tests are not reliable indicators of body burden, and urine porphyrins commonly results in false negatives, although it would be one more piece to the puzzle.
A hair test is relatively inexpensive and reasonably accurate, and it provides some other useful information about mineral status. Although it doesn't provide good information regarding your level of toxicity, it will allow for a confirmatory diagnosis in most cases...just make sure you have someone who knows what they are doing provide the analysis.
If you don't have amalgam fillings or other very recent mercury exposure, consider just doing a single round of low dose DMSA chelation...the presence of symptoms will tip you off to your toxicity. Of course if you opt for this route, you need to read up on chelation.