I believe it's a global scoring system Janieg but it is primarily used by the NHS because of the great expense of biologic drugs.

I'm interested to know how your idiopathic SFN is judged to be non progressive to date? I feel mine is progressing steadily because the tingling, burning, damp sensation has spread to above my knees and elbows from just affecting ankles and wrists over the past 18 months or so. But I'm not sure how this could be evidenced clinically and it didn't show up in my nerve conduction tests? Do you need regular skin biopsies to assess whether or not it is actually progressing?