--to have a skin biopsy for intraepidermal nerve fiber density done at just one location, because, as en bloc points out, one can't get an idea whether the neuropathy might be length-dependent that way.

Usually, samples are taken right above the ankle and at the side of the upper thigh, which are the areas for which the original norming at Johns Hopkins was done back in the late 90's--I've been talking about this in the other thread that RunWriteMomHeal started:

http://neurotalk.psychcentral.com/thread231571.html

Sometimes samples are also taken from the upper arm and near the wrist, which were normed later at various institutions and can also show length dependency.

Among the facilities that have the electron microscopy and pathology interpreters to do this are:

Johns Hopkins (Baltimore)
Cornell Weill/Columbia Presbyterian (New York)
Jack Miller Center (Chicago)
Massachusetts General (Boston)
Jacksonville Shands (Jacksonville, Florida)
Washington University Neuromuscular Center (St. Louis)
University of California at San Francisco Medical Center

There may be a few others now, but this is not something that your average hospital does.