The medical professionals who are treating my Lyme, have clinical experience with this approach and recommend it because they see it help their patient popluation. So I'm going to work with them on this and trust their clinical judgment. And if it's too much for my body, then I'll take a different approach. My turn to be the guinea pig.

They are doing a full CBC panel and mineral testing at baseline and I will retest everything again at the end.
In terms of heavy metals and Lyme, a good resource for that is Chapter 8 in the Dr. Horowitz book, "Why Can't I Get Better? Solving the Mystery of Chronic Lyme and Disease".
I was a chemist for over 13 years and was
directly exposed to many of the things on my testing panel; I've had way more exposure to a wide variety of chemicals and radiation compared to an average person. We were going to run another panel that tested for more obscure chemicals that I had directly worked with, but there is no point in wasting my money on that since I opted for chelation. I've had both acute and chronic exposures during my time in the lab....
I don't think chelation is right for the majority of people and there are many safe natural ways to detox. I put a fair amount of thought into deciding to do this. I've had another medical opinion on this topic beforehand. They had the same concerns with my prior profession and were going to take the same approach.
The reference ranges on that test I took were based the knowledge that people will have metals in their system. It's an unfortunate fact of modern life - especially if you are a woman. My results mean that I was above the average person's exposure level. What is interesting is that I was taking ALA, NAC, green algae tabs plus eating well for a long time, so my attempts at naturally removing these substances has not moved the needle much.
One note of interest, I had a MRI with contrast early in 2014. It's almost 2 years later and it is still in my system. I had not expected this to be the case.
If get a chance, I'll try to post a few pub med articles later.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4144270/