I recently had a fat pad biopsy (within the last few weeks) to check me for amyloidosis. It wasn't the most pleasant of procedures, and one neurologist I visited said he thought it was a waste of my time, but I decided to do it anyway. My primary neurologist ordered this when he was nearing the end of all the other tests we had tried. Since I have not been given a formal diagnosis (so technically it is still idiopathic), I thought I should at least rule this out. Amyloidosis is a serious condition, and should be treated, so it wasn't like it was all for nothing.