Heavy metal toxicity from fish can be assessed by checking blood levels of lead, arsenic, cadmium, and mercury, with provoked tests potentially offering a more long-term measure.

“check your heavy metals check your lead check your arsenic check your cadmium check your mercury you can check blood levels of these things it's super easy you don't need to do a provoked test although they are stored in bones and a provoked test may be a more accurate measure or it may give you another data point you can just get a blood level of lead cadmium arsenic mercury and get a sense of how heavy metal toxic you are now the blood levels will be more acute a provoked test with dmsa dmso or edta may be a little more long-term in terms of your stores of these heavy metals”