Hi - my diagnosis has never really been confirmed as autoimmune or otherwise - but the doc got approval from Medicare with no problem - just called it CIPD - even though my Sjogrens biopsy - ANA - etc were normal... I dont know if its because the nerve damage is obvious on both sural nerve biopsy and NCS/EMG - but they have never questioned - I believe many insurances pay now for "idiolpathic" type situations......