I've often read about metals tests giving false negatives. I suppose it's also possible that some tests may give a false positive.
Perhaps if you could give us a more complete idea of symptoms you've had, things you've tried, how you've reacted, etc. There are things which share symptoms with heavy metal toxicity but aren't necessarily caused by heavy metals (hypothyroidism, for example).
You could put this information in a new thread on this list since more people may read it that way. Of course, maybe you've already done that, and I just haven't seen it.