And Andy Cutler is an expert. He applied statistics to a ton of hair tests and simplified the statistics into what he calls the five counting rules. Just do a search on that phrase.
Anyone can apply the rules and see if someone meets the rules and is potentially toxic. Andy's work is with Doctor's Data hair tests.
Sorry if I am speaking to the choir here but it sounds like you might not be acquainted with Andy's work.
Admittedly, some tests appear borderline, and some people don't meet the rules but are so clearly toxic they have to try chelating to see what happens and see if it makes sense to continue......