I would like to know the reliability of food intolerance tests?

I have 10 Sivler fillings but not intolerant to Yeast so does that mean Im ok and not have candida? I have wheat sensitivity though.

Whats the best diagnostic test for mercury and candida?

And is mercury bad in everyone as my bro has many silver fillings and he is a doctor and happily married with 4 kids so not all fillings are bad and some people dont react i guess.