Muscle biopsy

Definition

A muscle biopsy is the removal of a small piece of muscle tissue for examination.

How the Test is Performed

This procedure is usually done while you are awake. The health care provider will apply a numbing medicine (local anesthesia) to the biopsy area.

There are 2 types of muscle biopsy:

After either type of biopsy, the tissue is sent to a laboratory for examination.

How to Prepare for the Test

No special preparation is usually needed. If you will have anesthesia, follow instructions on not eating or drinking anything before the test.

How the Test will Feel

During the biopsy, there is usually little or no discomfort. You may feel some pressure or tugging.

The anesthetic may burn or sting when injected (before the area becomes numb). After the anesthetic wears off, the area may be sore for about a week.

Why the Test is Performed

A muscle biopsy may be done to identify or detect:

A muscle biopsy may also be done to tell the difference between nerve and muscle disorders.

A muscle that has recently been injured, such as by an EMG needle, or is affected by a pre-existing condition, such as nerve compression, is not a good choice for a biopsy.

Normal Results

A normal result means the muscle is normal.

What Abnormal Results Mean

A muscle biopsy can help diagnose the following conditions:

There are additional conditions under which the test may be performed.

Risks

The risks of this test are small, but may include:


Review Date: 7/21/2016
Reviewed By: Gordon A. Starkebaum, MD, Professor of Medicine, Division of Rheumatology, University of Washington School of Medicine, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.

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