Please take a look at this relatively recent set of info regarding auto-immune CIDP... It does address the issue of 'nerve biopsies' as important or not to diagnosis.
http://www.cidpinfo.com/diagnosis/index.aspx It includes two different 'set's of diagnostic criteria...you can tell if a doc is 'up to date' by how they approach all this?
I bring this up because the skin punch biopsy is FAR FAR preferable to diagnose neuropathies than what's called a full 'Seural Nerve Biopsy'.
I also bring this up because many here in the past have undergone this latter procedure with some complications and side effects. The only thing that it could do.....The Seural biopsy, that is, is prove that nerves are DEAD! The side effects of the procedure are rife with potential infections and many stellar insurance companies no longer cover this procedure as one necessary for diagnosis.
I had encountered one neuro [briefly for all of two office visits] until he'd suggested that I have this 'procedure'. I thot it peculiar until I realized that HE wanted to get this 'procedure' on his resume, when all other tests were clearly indicating my diagnosis - according to that CIDP-info site.... This was in 2004. I am truly glad that I'd declined!
Do the skin punch biopsy first, and if THAT is inconclusive, maybe then consider a seural biopsy...but only after really, really looking at all the pro's and cons. To me it's a very nasty procedure that seems now to be 'out of favor' and honestly? FINE BY ME! I was lucky enough that other testing [a sort of 9 out of 10 rule {biopsy excluded}] enabled me to escape the seural biopsy. In '04, the punch biopsy was still considered VERY 'experimental'. I do believe it's gonna be accepted practice soon, as it's soo much less invasive.
In all honesty, all either will do is tell you that existing skin has DEAD NERVES. It can prove your case for some things? But, it really will not change one whit how you are treated, nor how well.
Pain control, lifestyle modifications, and any immune therapies are key to getting by/and on with this stuff. Any which way, it's no pic-nic for sure! And we just hunker down and get on with it all as best we can. 's - j