Any doctor who is trained can do the punch biopsies. I think podiatrists can’t, because they cannot work on anything but the foot area, per their title. I had mine done by a pain doctor who does them on a consultation basis - meaning I was not seeing him for pain, just sent there by my neurologist for the biopsy. I imagine a dermatologist would have the training and set-up to perform the biopsy.
It is standard to take three samples - ankle, knee and upper thigh. It has to be ordered by your doctor. So your doctor would know where to send you.
It’s not a complicated procedure, but like any biopsy, the sample has to be correctly prepared, sent to the appropriate lab, and then the results have to be interpreted by the doctor.