Therapath Neuropathology

Small Fiber Neuropathy Testing

Therapath provides Epidermal Nerve Fiber Density (ENFD) and Sweat Gland Nerve Fiber Density (SGNFD) testing for the evaluation of Small Fiber Neuropathy. Results are available in 7-10 days.

In-Office Biopsy Procedure

Demonstration of a reduction in the Epidermal Nerve Fiber Density (ENFD) on punch skin biopsy is a highly sensitive and specific test for Small Fiber Neuropathy (SFN).1

Samples are collected using a 3mm punch biopsy. The brief procedure does not require sutures and is reimbursed by insurance (CPT 11104 and 11105).

Biopsy procedure guide

Convenient Biopsy Kits

Kits include everything needed for the procedure except for lidocaine and a syringe.

Collection kits are shipped via overnight service and are temperature controlled to protect samples during transit.

Order Biopsy Kit


Small Fiber Neuropathy Overview
Small fiber neuropathy (SFN) is caused by damage to the small, unmyelinated fibers in the peripheral nerves that innervate the skin and internal organs, including the cardiovascular system, gastrointestinal tract, and bladder, among others. These fibers convey pain and temperature sensations from the skin, and mediate autonomic functions. Dysfunction of the small nerve fibers can cause sensory or autonomic symptoms…

Epidermal Nerve Fiber Density (ENFD)
Demonstration of a reduction in the Epidermal Nerve Fiber Density (ENFD) on punch skin biopsy is a highly sensitive and specific test for Small Fiber Neuropathy (SFN)…

Sweat Gland Nerve Fiber Density (SGNFD)
Sweat glands are exocrine glands in the deep dermal and subcutaneous layers of skin, whose function is to maintain the body’s temperature and hydration…

Small Fiber Neuropathy in Fibromyalgia and other Rheumatological Disorders
Patients with rheumatological disorders can present with a variety of syndromes that can result from Small Fiber Neuropathy (SFN). Several recent studies found that approximately 50% of fibromyalgia patients had reduced Epidermal Nerve Fiber Density (ENFD), consistent with SFN…

Cancer Related Neuropathy
Peripheral neuropathy is not uncommon in patients with cancer. It can result from the underlying cancer, poor nutritional status, paraneoplastic mechanisms, or neurotoxicity of drugs used to treat the tumor. Pre-existing neuropathy is also a risk factor for development of early or more severe chemotherapy induced neuropathy…

Statin Neuropathy
Treatment with statins, or HMG-CoA-reductase inhibitors, reduces the risk of cardiovascular disease in patients with hypercholesterolemia…

Neuropathy and Amyloidosis
Neuropathy can be an early manifestation of systemic amyloidosis. Such patients often present with a painful distal and symmetric neuropathy and autonomic symptoms…


Lauria G, Bakkers M, Schmitz C, et al. Intraepidermal nerve fiber density at the distal leg: a worldwide normative reference study. J Peripher Nerv Syst. 2010;15(3):202-207. [PubMed]