Hi Steve, Thermal threshold testing did show up my small fibre damage, & an EMG showed some damage to the large nerves as well, but thermal threshold testing doesn't always show the small fibre damage as Glentaj said, if i remember right it didn't work for him, but a skin punch biopsy did, the only trouble is finding a lab in Melbourne that does it, i do not know of any myself, but if you have the symptoms of small fibre damage and that thermal test showed abnormal reactions why bother, the important thing is to find the cause, which isn't always easy.
good luck
Brian