Epidermal nerve fiber density consultation

Alphabetical Test listing

Epidermal nerve fiber density consultation-994

Epidermal nerve fiber density consultation
Skin punch biopsy
Small fiber neuropathy

Investigation of polyneuropathies

Tissue, skin punch biopsy

Kit has a shelf life of 3 months. 

  • Order kit so it is received a day or 2 before procedure, ensuring fresh solutions and adequate time in case of shipping delays (eg, delay due to weather). To order kits, call 800-533-1710 and ask for the Peripheral Nerve Lab, or call direct to 507-284-8065
  • A kit contains 2 sets of vials for 2 biopsy sites.
    • One set is labeled “Site 1” and the other set is labeled “Site 2.”
  • Place kit immediately in a 4°C refrigerator until ready to use.
  • Do not use other fixatives or buffers.

Preferred source:

Distal leg, mid-thigh, dorsal foot, and lower abdomen

Collection Instructions:

MCL - Epidermal Nerve Fiber Density Instructions - MC4091-41 (mayocliniclabs.com)

  • The standard biopsy for evaluating distal small fiber sensory neuropathy includes two 3-mm skin punch biopsies from the same side of the body.
  • Prepare and transport specimen per instructions



Specimen processing will occur at the collecting location, not the lab.

Perform the following for each biopsy:

  1. Place 3-mm skin punch biopsy in Vial A (Zamboni fixative) as soon as it’s removed from patient.
    1. Carefully place specimen in the correct site vials, submerging the tissue in the liquid for each step. Put lid on vials, making sure specimen is not caught on threads. Invert vials gently so that specimen sinks to the bottom of the vial.
    2. Record on vials the location of Site 1 and Site 2 (dorsal foot, distal leg, mid-thigh, or lower abdomen). Also label each vial with:
      • Site
      • Patient name
      • Birth date
      • Side
  2. Fix specimen in Vial A (Zamboni fixative) for 12 to 24 hours in a 4°C refrigerator. Do not exceed 24 hours as this will affect the quality of the immunohistochemistry results.
  3. After 12 to 24 hours in Vial A (Zamboni fixative), transfer specimen to Vial B (0.1 M Sorenson’s Phosphate Buffer) to rinse for 30 minutes.
  4. After 30 minute rinse, place specimen in Vial C (Cryoprotectant) for shipping.
  5. Place Vial C in a 4°C refrigerator until the specimen is shipped.
  6. Complete the Epidermal Nerve Fiber Density Patient Information (T702) form; specimens will not be processed if information is not completed. MCL - Epidermal Nerve Fiber Density Patient Information - MC1235-179 (mayocliniclabs.com)

7. Bring completed kit to the lab for shipping.


Vial C (in kit)


Refrigerated (preferred)

Ambient - OK

Frozen - NO

  • Specimens received in an expired kit
  • Incomplete Epidermal Nerve Fiber Density Patient Information (T702) form
Mayo Clinic Laboratories (SPBX): R-NX
Mo - Fr
12 - 20 days

Calculation of epidermal nerve fiber density


A consultative report will be provided.

The number of intraepidermally originating nerve fibers that cross the basement membrane between the dermis and epidermis are counted in several sections. The total linear length of the epidermis is measured using standard morphometric techniques and a density of epidermal nerve fibers (number of fibers/mm) is reported. This value is compared to previously published normative data.

If appropriate: