This is why they call medicine a practice, and a dx an opinion. There's a lot of science and fact, but the big picture is often an educated guess based on best available information, experience, and sometimes even a hunch or two.

Yes, I have had this happen to me - several times. There's even an old joke about it (sort of).*

Since the doctor that you have trust & confidence in had some concern about you/your treatment and sent you to the teaching hospital, what does she think about your going through with the additional tests?

From my own experiences, I'd try to have a discussion with both doctors (separately) and try to find out what's up. What are they trying to determine or rule out, what are their concerns & why, etc. I wouldn't be confrontational, or try to pit them against each other (that may shut them down or cause them to put up a defensive wall), but I would be firm about wanting to be informed and involved in my care/treatment. Then I'd probably list/consider the pros & cons (upsides/downsides, benefits/risks).

Since it's a bit of a distance (or maybe just becuz) I might go over that last part a couple times (i.e. sleep on it) to see if my answer changes or I needed more information.

HTH,

Doc

* http://neurotalk.psychcentral.com/post705387-32.html

I had the same situation, my neurologist was pretty certain I had an inherited neuropathy, and no possible treatment, but she wanted to be sure. It really seemed to bother her because I was only 47, with 5 kids, and this progressive, incurable condition, and all they could do was prescribe pain meds. She sent me to Johns Hopkins, less than a two hour trip for me. The findings were not substantially different, but they did the skin punch biopsy and some of the Athena tests for CMT, as well as a two hour EMG / NCS. Diagnosis - severe small and large fiber polyneuropathy, probable CMT. I also have pinched nerves at wrists and elbows, but test for HNPP was negative.
So my two doctors didn't disagree, and they both supported my decision not to pursue further Athena testing since there is no treatment, but they more or less washed their hands of me and referred me to my family doctor for pain management. Actually the doctor at Johns Hopkins was happy to pursue it if I wanted to, but did say it was unlikely to be productive.
Dr. Smith's advice is sound. Additional tests for untreatable neuropathies seem pointless, but if there is some condition that is treatable for which you haven't been tested, by all means pursue it.