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Epidermal Nerve Fiber Density Testing

Test for small fiber peripheral neuropathy in your practice today

What is Epidermal Nerve Fiber Density (ENFD) Testing?

ENFD testing is the clinical standard test for diagnosing small fiber peripheral neuropathy. Skin tissue is removed using the standardized punch biopsy procedure.

 

Once the preparation and immunohistochemical staining of the tissue specimen has occurred, it is placed under microscope for examination. Our pathologists use precise guidelines to then inspect the structural integrity of the small nerve fibers and evaluate the number of small nerve fiber endings.

Gray nerve fiber

What is Small Fiber Peripheral Neuropathy (SFPN)?

SFPN takes place in peripheral regions in the body - feet, legs, hands, arms - and occurs when damage to the peripheral nerves affects small somatic and autonomic fibers. These fibers are responsible for detecting and sending information to help regulate involuntary bodily functions.

 

Individuals could have SFPN yet test negative on electromyography and nerve conduction studies because small fiber damage can occur without large fiber involvement. SFPN can result in debilitating pain if not properly diagnosed and managed. ENFD testing looks specifically at small nerve fibers and remains the best test for diagnosing small fiber peripheral neuropathy.

Small gray and oranger nerve fiber endings
Gray and orange small nerve fibers
WHAT DO AUTONOMIC AND SOMATIC FIBERS DO?
  • Internal temperature regulation (generate or dissipate heat through blood vessel constriction or dilation, sweating, shivering)

  • Feelings of sensations such as cold, hot, pain, itching, smooth, rough, pressure, tickling, and vibrations

  • Sweat gland activity

  • Cardiovascular (heart rate and blood pressure regulation)

  • Temperature perception (detecting hot and cold)

  • Gastrointestinal (digestion rate and enzyme secretion)

  • Urogenital (bladder function and sexual arousal)

SYMPTOMS OF SMALL FIBER PERIPHERAL NEUROPATHY MAY INCLUDE
Common Symptoms
  • Tingling or numbness in toes or feet

  • Burning pain (often persistent)

  • Electric shock-like pain (lasting few seconds)

  • Feeling of walking on sand, pebbles, or golf balls

  • Restless legs

  • Bedsheet touching legs or feet is irritating or painful

Less Common Symptoms
  • Dry eyes and mouth

  • Abnormal sweating

  • Incontinence or abnormal urination frequency

  • Constipation

  • Orthostatic hypotension (a quick drop in blood pressure upon standing)

  • Sexual dysfunction

Orange and yellow glowing neurons.webp
THE FOLLOWING CONDITIONS ARE ASSOCIATED WITH PERIPHERAL NEUROPATHY
  • Diabetes

  • Hyperlipidemia

  • Chronic alcohol abuse

  • Hypothyroidism

  • Metabolic syndrome (as indicated by hyperlipidemia, hypertension, obesity, abnormal glucose metabolism with insulin resistance)

  • Neurotoxic drug exposure (chemotherapy; vaccine-associated; antibiotics)

  • Vitamin B12 deficiency

  • Hereditary conditions (Fabry’s disease; Wilson’s disease; familial amyloidosis)

  • Autoinflammatory diseases and immune-mediated conditions (celiac disease; fibromyalgia; lupus; rheumatoid arthritis; Sjogren’s syndrome; sarcoidosis)

  • Infectious diseases (Hepatitis C; Lyme disease; HIV)

  • Abnormal glucose metabolism or glucose intolerance (as indicated by abnormal 2-hour glucose tolerance test or abnormal fasting glucose levels)

  • Copper deficiency

*A large number of cases have an unidentifiable cause

Microscopic ENFD testing
ENFD TEST DETAILS

Methodology

  • 3mm punch biopsy & placement in Zamboni’s fixative

  • Immunohistochemical staining

Specimen

Skin

Patient Preparation

None

Stability

Biopsy must fix for minimum of 8 hours & maximum of 24 hours

Transport Temperature

Specimen shipped overnight with freezer pack

DIAGNOSIS WITH DEGREE OF SEVERITY FOR SFPN

NERVE FIBER DENSITY MEASUREMENT

STAINING FOR VASCULITIS & AMYLOID

ENFD Test Report

Mobile access for providers & patients

Result notifications

EMR integration

Colored microscopic images

Next Genomix ENFD lab report on tablet

Additional Testing Services

African american woman with dna helix on high cheek

Pharmacogenetic

onychodystrophy testing bare feet with zoom in pathogens

Onychodystrophy

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