Epidermal nerve fiber density (ENFD) testing is a technique used by neurologists for many years. This particular modality is based on the idea that most forms of peripheral neuropathy progress is from a more distal to a more proximal area of the body, starting with the smallest nerve fibers (C and A delta fibers) and then progressing proximally. This explains why most of the diabetic patients present with a so called "stocking-glove" distribution (i.e. feet-hands) type of peripheral neuropathy.
What ENFD testing does, it measures the amount of small nerve fibers utilizing a 3 mm punch biopsy of skin. In so doing it may be used to determine the amount of nerve damage to the C and A delta fibers.
There are a few advantages in using this type of testing for peripheral neuropathy over other techniques which are as follows:
- It is the only test to measure directly small fiber neuropathy
- It measures the quantity of fibers present ( objectively)
- It is more sensitive than quantitative sensory testing
- It is more sensitive and more invasive than sural nerve biosy
- It's diagnostic efficiency is 88%.
- It may predict the onset of neuropathy even before symptoms begin
- It is easily performed in our office in about 10 -15 minutes
- It is used to measure not only the severity of the small fiber neuropathy but also can be used to measure the treatment response to a particular medicine or any other treatment modality. Therefore, the ENFD testing is done at the beginning of a particular treatment and then in about 6 months is may be repeated to see if that particular treatment is actually working or not.