Does a skin biopsy show inflammation?
My atypical CIDP diagnosis came after a VGKC antibody was present. I also had a sural nerve biopsy which showed an inflammatory process going on.
I think skin biopsy's are less invasive and have replaced nerve biopsy's in most cases.
Having the diagnosis is very helpful in getting insurance coverage for the IVIG.
If there is any possibility that your neuropathy is due to your immune system then it is worth trying the IVIG. It is not harmful, worst case scenerio is, it won't do anything and they will stop it after 3 or 4 treatments.