--is, fortunately, one of the most benign procedures you'll probably ever experience.

At each location from which a sample is to be taken, you will be given a shot of a local anesthetic, such as xylocaine--which will probably be the only discomfort you will experience (it sometimes burns a bit going in). Then, after a few minutes to give that time to numb the areas, small, 3mm diameter circles of skin will be carved out (usually to a depth of 1 mm) of each. Normally, samples are taken at the ankle and thigh, and sometimes the lower and upper arms (this is to check for the nerve fiber "length-dependency" of many suspected neuropathies).

You will bleed a little from each sample, but since the smaples are small this will stop quickly with some pressure and gauze. Normally, a band-aid on each spot is all that is needed--the samples are too small to require stitches. You'll probably be given instructions to keep the bandages on for a while and some care instructions that may include a topical admnistration of local antibiotic ointment once they come off, just as precuation.

It normally takes a while before you get results; what is looked for is intraepidermal nerve fiber density and the condition of those nerves (compared with "normal" controls). Significantly reduced density, or abnormal swelling/branching of fibers, often points to a small-fiber neuropathy, though cause is rarely revealed by skin biopsy.

I've had this done four times--I'm followed for research purposes--and my skin biopsies (after the first one, which showed major reduction in density and abnormal branching/swelling) have shown slow re-enervation over the years. The procedure is so ho-hum I'd let them do it every month if they felt it necessary.