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Test Code PNBX Peripheral Nerve Pathology Consultation


Additional Testing Requirements


Biopsies from different sites require separate orders and separate specimen vials.

Example:

One (1) left sural nerve and 1 left superficial peroneal nerve require 2 separate orders, one for each type of nerve.



Shipping Instructions


Ship Monday through Thursday.

Transport specimen per Nerve Biopsy Specimen Preparation Instructions (T580).



Necessary Information


The following information is required:

All requisition and supporting information must be submitted in English.

 

Each of the following items is required:

1. All requisitions must be labeled with:

-Patient name, date of birth, and medical record number

-Name and phone number of the referring pathologist or ordering provider

-Anatomic site and collection date

2. Nerve Biopsy Patient Information (T458)

3. Additional clinical information:

-Neurology clinical notes

-Electromyography results if performed



Specimen Required


Specimen Type: Nerve biopsy tissue, slides, or block

Supplies: Nerve Biopsy Kit (to order call 507-284-8065 or 800-533-1710)

Collection Instructions: Prepare and transport specimen per Nerve Biopsy Specimen Preparation Instructions (T580).


Forms

Nerve Biopsy Patient Information (T458) is required

Secondary ID

70598

Useful For

Evaluating diseases of the nerve and disorders that affect nerve function

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
SS2PC SpecStain, Grp II, other No, (Bill Only) No
COSPC Consult, Outside Slide No, (Bill Only) No
CUPPC Consult, w/USS Prof No, (Bill Only) No
CRHPC Consult, w/Comp Rvw of His No, (Bill Only) No
NTFPC Teased Fiber No, (Bill Only) No
IHPCI IHC Initial No, (Bill Only) No
IHPCA IHC Additional No, (Bill Only) No
LV4RP Level 4 Gross and Microscopic, RB No, (Bill Only) No
CSPPC Consult, w/Slide Prep No, (Bill Only) No
EM Electron Microscopy Yes, (Bill Only) No

Testing Algorithm

A battery of enzyme histochemical stains or immunostains are performed; other tests can be performed as indicated at an additional charge. The reviewing neuromuscular pathologist will determine the need for additional testing.

 

Wet tissue for consultation: When adequate tissue is provided, routine testing will include teased fiber examination, Congo red stain, methyl violet stain, Masson's trichrome stain, leukocyte common antigen, luxol fast blue/PAS (periodic acid-Schiff) stain, KP-1 macrophage, methylene blue stain, hematoxylin and eosin stain, and Turnbull blue stain or Perl's Prussian blue stain.

 

Slides and blocks sent for consultation: Special stains and studies performed on the case should be sent with the case for review. In order to determine an accurate diagnosis, some of these stains or studies may be deemed to warrant repeat testing, at an additional charge, at the discretion of the reviewing Mayo Clinic neuromuscular pathologist. In addition, testing requested by the referring physician (immunostains, molecular studies, etc) may not be performed if deemed unnecessary by the reviewing Mayo Clinic neuromuscular pathologist. For all consultations, ancillary testing necessary to determine a diagnosis is ordered at the discretion of the Mayo Clinic neuromuscular pathologist. An interpretation, which includes an evaluation of the specimen and determination of a diagnosis, will be provided within a formal pathology report.

 

For more information see Pathology Consultation Ordering Algorithm.

Method Name

Nerve Biopsy Surgical Pathology Consultation and Review of Outside Material

Reporting Name

Peripheral Nerve Path Consult

Specimen Type

Varies

Specimen Stability Information

Specimen Type Temperature Time Special Container
Varies Refrigerated (preferred)
  Frozen 

Reject Due To

  All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.

Clinical Information

Neuropathy is a common neurological complaint and a frequent source of morbidity in many patient populations. Direct investigation of small fiber involvement has been limited as most classical techniques (eg, electromyography, nerve conduction studies, and nerve biopsy) focus on large diameter nerve fibers and may be normal in patients with small fiber neuropathies.

 

Nerve biopsies provide information about nerve fibers and the interstitium of the nerve. Neuropathic abnormalities include decreased density of myelinated fibers, segmental demyelination, and axonal degeneration. Some possible interstitial abnormalities that affect nerves include necrotizing vasculitis and amyloidosis.

 

This consultation is for fixed tissue, slides, or blocks.

Reference Values

An interpretive report will be provided.

Interpretation

The clinical and neurological history is reviewed with the interpretation of the biopsy.

 

The histologic slides, special stains, and history, along with the physician's report are correlated by a neuromuscular pathologist. An interpretive report will be provided.

Cautions

Poor fixation, orientation, and improper handling of the nerve tissue may hinder the neuromuscular pathologist's interpretation of the biopsy. For more information see Nerve Biopsy Specimen Preparation Instructions. Kits containing the proper tissue fixatives and buffers are available upon request.

Method Description

A battery of special stains and teased nerve fiber analysis will be performed if fixed tissue is provided. Nerve morphometry and electron microscopy to determine diameter size histograms and ultrastructural abnormalities may be performed based on a preliminary review by the neuropathologist.(Unpublished Mayo method)

Day(s) Performed

Monday through Friday

Report Available

7 to 14 days: Cases requiring additional material or ancillary testing may require additional time.

Specimen Retention Time

Material made at Mayo Clinic may be retained at Mayo Clinic indefinitely.

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

88305 (if appropriate)

88313 (if appropriate)

88321 (if appropriate)

88323 (if appropriate)

88323-26 (if appropriate)

88325 (if appropriate)

88362 (if appropriate)

88348 (if appropriate)

88342 (if appropriate)

88341 (if appropriate)

LOINC Code Information

Test ID Test Order Name Order LOINC Value
PNBX Peripheral Nerve Path Consult In Process

 

Result ID Test Result Name Result LOINC Value
601774 Interpretation 59465-5
601775 Participated in the Interpretation No LOINC Needed
601776 Report electronically signed by 19139-5
601777 Addendum 35265-8
601778 Gross Description 22634-0
601779 Material Received 81178-6
601823 Case Number 80398-1
601912 Disclaimer 62364-5

Clinical Reference

1. Tracy JA, Dyck PJ, Klein CJ, Engelstad JK, Meyer JE, Dyck PJB. Onion-bulb patterns predict acquired or inherited demyelinating polyneuropathy. Muscle Nerve. 2019;59(6):665-670

2. Xu M, Pinto M, Sun C, et al. Expanded teased nerve fibre pathological conditions in disease association. J Neurol Neurosurg Psychiatry. 2019;90(2):138-140

3. Dyck PJB, Spinner RJ, Amrami KK, Klein CJ, Engelstad JK, Dyck PJ. MRI-targeted fascicular nerve biopsies of proximal nerves: historic reports and illustrative case reports. In: Dyck PJ, Dyck PJB, Engelstad JK, et al, eds. Companion to Peripheral Neuropathy: Illustrated Cases and New Developments. Elsevier; 2010:3-14

4. Dyck PJ, Dyck PJB, Engelstad J. Pathologic alterations of nerves. In: Dyck PJ, Thomas PK, eds. Peripheral Neuropathy, Vol 1. 4th ed. Elsevier; 2005:733-829

Highlights

Our consultative practice strives to provide the highest quality diagnostic consultative service, balancing optimal patient care with a cost-conscious approach that supports the rapid turnaround time for diagnostic results.

Specimen Minimum Volume

4.5 cm biopsy