A nerve biopsy is the removal of a small piece of a nerve for examination.
Biopsy - nerve
How the test is performed
The sural nerve (in the ankle), or the superficial radial nerve (wrist) are the sites most often used for biopsy. A local anesthetic is used to numb the area. A small incision is made, and a portion of the nerve is removed. The sample is then examined using either a regular (light) microscopic or an electron microscope. Individual nerve fibers may also be examined.
How to prepare for the test
There is no special preparation.
How the test will feel
The amount of pain during and after the procedure depends on the patient. Because a local anesthetic is used, discomfort during the procedure is usually minimal. The anesthetic may burn or sting when first injected. After the procedure, the area may feel tender or sore for a few days.
Why the test is performed
Nerve biopsy may be done to help diagnose:
There is normal nerve anatomy, with no abnormal growths or inclusions.
Note: Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.
What abnormal results mean
Conditions or disorders that may be revealed include:
- Amyloidosis (sural nerve biopsy is most often used)
- Inflammation of the nerve
- Loss of axon tissue
- Metabolic neuropathies
- Necrotizing vasculitis
Additional conditions under which the test may be performed:
- Alcoholic neuropathy
- Axillary nerve dysfunction
- Brachial plexopathy
- Charcot-Marie-Tooth disease (hereditary)
- Common peroneal nerve dysfunction
- Distal median nerve dysfunction
- Mononeuritis multiplex
- Necrotizing vasculitis
- Radial nerve dysfunction
- Tibial nerve dysfunction
What the risks are
- Allergic reaction to the local anesthetic
- Discomfort after the procedure
- Infection (a slight risk any time the skin is broken)
- Permanent nerve damage (uncommon; minimized by careful site selection)
Nerve biopsy is invasive and is useful only in certain circumstances. These include diagnosis of asymmetric and multifocal nerve disorders, conditions in which a nerve enlargement can be felt with the fingers, and suspected inherited pediatric nerve disorders.
Shy ME. Peripheral neuropathies. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier. 2007: chap 446.
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; Daniel B. Hoch, PhD, MD, Assistant Professor of Neurology, Harvard Medical School, Department of Neurology, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.