Therapath Neuropathology

Epidermal Nerve Fiber Density Test – Biopsy Sites

March 27, 2018

Standard Biopsy sites for ENFD Testing

Therapath has established five standard biopsy sites for Epidermal Nerve Fiber Density (ENFD) and Sweat Gland Nerve Fiber Density (SGNFD). These sites allow for the diagnosis of a Small Fiber Neuropathy affecting either the upper or lower extremities in patients 18 and older.

The standard sites include the Proximal Arm, Distal Arm, Thigh, Distal Leg, and Foot. More details are available on our biopsy procedure guide.

The Epidermal Nerve Fiber Density (ENFD) test measures the density of the small sensory nerve fibers in the skin, and the Sweat Gland Nerve Fiber Density (SGNFD) test measures the density of the small autonomic nerve fibers in the sweat glands.1,2 The same biopsy sample can be used for both tests.

The skin biopsy procedure can be performed at the physician’s office and is reimbursed using CPT codes 11100 and 11101.

Small Fiber Neuropathy Testing


Joint T. European Federation of Neurological Societies/Peripheral Nerve Society Guideline on the use of skin biopsy in the diagnosis of small fiber neuropathy. Report of a joint task force of the European Federation of Neurological Societies and the Peripheral Nerve Society. J Peripher Nerv Syst. 2010;15(2):79-92. [PubMed]
Gibbons C, Illigens B, Wang N, Freeman R. Quantification of sweat gland innervation: a clinical-pathologic correlation. Neurology. 2009;72(17):1479-1486. [PubMed]