My Nerve conduction study showed some minor discrepancy but nothing definitive. A skin biopsy is what gave me a firm diagnosis of small fiber neuropathy. My understanding is that SFN or peripheral neuropathy can really only be diagnosed through skin biopsy. This is where the nerve fibers are stained and counted in a given area. Here is a site that describes the test:

http://www.therapath.com/Why_perform.php

Best of luck in finding your answer.

Mere