A skin biopsy is a procedure in which a small sample of skin tissue (3 mm) is removed. This takes place about 10 cm above the ankle under local anaesthesia.

After the biopsy is taken, the tissue is placed in a specimen container. The specimen is then sent to the pathology laboratory, where the tissue is further prepared and stained, in order to count the number of small nerve fibres. In patients with small fibre neuropathy the density of small nerve fibres is decreased compared to healthy persons of the same age and gender.