https://www.sophiahi.com/testing-heavy-metals/Most tests of heavy metals seem to catch only your body's DETOXIFICATION ability, meaning, that if you are ABLE to detox metals, they will show up in hair, stools etc.
Everyone is toxic with many toxins, but the more metals you have in the hair and stools, it means you are excreting them, so your load may be lower.
The less metals you have in your hair sample may mean exactly the opposite: you are more toxic with them, as you can't excrete them !!
that's the whole methylation issue that's discussed today, in so many chronic illness.
The best test is Oligoscan (expensive), that does a spectrum analysis, the same way as we know which elements are in the stars.
it does not depend then on your excretion ability as it will read from your cells!!