Brian's referred sites should be good for starters, also at the top of the PN page are a group of 'stickies' -the posts started by LizaJane are chock full of sites that will probably keep you reading till your mind fogs over. I recommend you doing about an hour's worth of reading a day. You'll be less confused that way and since neuropathies are soo confusing anyhow, mite as well do it in tolerable doses.
Neuropathies are presented in all sorts of medical conditions as well as being neuropathies in and of their own sets of conditions. That makes diagnosis a long process of eliminating other things, LOTS of other things.
www.lizajane.org does list all the tests for diagnosing PN but also relates to the tests for spinal issues that can cause PN. It's been put together my a member who has gone thru the WHOLE MILL in terms of getting diagnoses in both areas. The usual course of exams are 1]blood; 2]basic neuro exam {see www.Neuroexam.com }; 3]nerve conduction tests; 4] MRI's [to eliminate brain and spinal issues]; and last 5] more blood and spinal tap work-ups to determine or eliminate auto-immune issues. Some exam procedures require nerve biopsies but, these days many insurance companies are very reluctant to authorize these surgeries/tests as all of #'s 1-5 should tell you what the biopsies could confirm, and seural biopsies can result in permanent damage in an affected area-should your docs demand a biopsy [I HOPE NOT!] you, in turn should demand a 'punch' biopsy-but, that is a loong way down the diagnosis road.
For now, take a good look at the LizaJane lists and start getting copies of all the tests, etc., done to date to fill in the worksheets.
We all are looking forward to some progress in your diagnosis and also in some pain relief for you - keep faith, the hurt keeps our minds active and learning - Hugs! - j