--agreed, one can have a small-fiber neuropathy and not show signs of small-fiber de-enervation on skin biopsy according to the MacArthur protocols, which define signs of de-enervation as intraepidermal nerve fiber density below the 5th percentile that was determined by norming it on a fairly small sample of people not suffering from neuropathy. There is considerble variation in people's small-fiber density, though--for one thing, it tends to naturally reduce as we age--and sometimes, since there would have been no reason to do biopsy to enumerate the fibers prior to symptoms, one could have shown a significant drop from what one's "own baseline values" would have been and still not drop down below the fifth percentile, and therefor get a reading of "normal' nerve fiber density when it fact they may have personally have experienced enough of a drop to have symptoms.

But--this is important--even with normal density ranges--the biopsy can show excessive branching and selling of the fibers themselves, which is definitely indicative of a neuropathic process. That may point to a small-fiber neuropathy diagnosis even without being below the fifth percentile (I certianly had this). Often in that case one has caught the process at a moment before one has dropped to "abnormal" levels, and a follow up biopsy might show even lower values.

In my case, for example, my first skin biopsy showed I was at the second percentile for intraepidermal nerve fiber density at the ankle and about 4% at the thigh, but if I'd had a few more fibers at the thigh that reading would have been normal. A subsequent biopsy 18 months later showed that I had started to re-enervate; then I had reached the 11th percentile at ankle and 12th at thigh, which is technically a "normal" result. But, of course, I still had some symptoms, and it was obvious I had suffered considerble de-enervation at a prior point. But at this point, I was not showing nearly as much swelling and damage of individual fibers.

My sense is that my original starting point, before all this, would have been at a much higher percentile (30? 50? 70? No one will ever know; there was no reason to get a biopsy then), and I did experience a major dimunition of fibers. I am unlikely ever to get back to my original percentile, but may re-enervate enough in time (re-enervatioon can go on for years if one has overcome the original de-enervation process, and doesn't start another) to have minimal symptoms, given that I continue to keep my blood sugar in check, take healthful supplements, etc.

I will always be thankful that I did show an "abnormal" count--it was the only unequivocally abnormal test I ever had in the whole investigatory process and provided evidence that this was not "all in my head"--an all too common designation too many of us have been slapped with. It's for that reason alone at times I would recommend the procedure, if one can get it, insamuch as it is not invasive or difficult--a few shots of Novacain/Xylocaine, a few 3mm samples taken, a few band-aids, and you're done--and if it does show abnormality, while one hasn't found a cause, one has documented that the symptoms are caused by something "real", which gets a little more respect from doctors, pharmacists, SSI boards, and friends and relatives.