This document addresses the pathological analysis from skin biopsy specimens of intra-epidermal nerve fiber (IENF) density for the diagnosis of small-fiber neuropathy (SFN). This document also addresses the pathological analysis of sweat gland nerve fiber density for the diagnosis of SFN. The assessment of nerve fibers is a component of evaluating peripheral nerve disease. Most nerve disease targets the small nerve fibers, (as opposed to large nerve fibers).

Clinical Indications

Medically Necessary:

Pathological analysis of intra-epidermal nerve fiber density for the diagnosis of small-fiber neuropathy is considered medically necessary when both of the following conditions are met:

1. Individual presents with painful sensory neuropathy; and
2. No evidence of large-fiber neuropathy is present on the following:
   1. Physical examination (for example, reduced or absent muscle-stretch reflexes or reduced proprioception and vibration sensation); and
   2. Electromyography and nerve-conduction studies.

Not Medically Necessary:

Pathological analysis of intra-epidermal nerve fiber density for the diagnosis of small-fiber neuropathy is considered not medically necessary in all other cases.

Pathological analysis of sweat gland nerve fiber density testing for the diagnosis of small-fiber neuropathy is considered not medically necessary for all indications.