What Is a Muscle Biopsy?

Medically Reviewed by Sanjay Ponkshe on February 24, 2024
4 min read

A muscle biopsy is a minor surgical procedure. Doctors order them to help diagnose certain diseases that involve muscles. During a muscle biopsy, a small piece of tissue is removed from a specific muscle. Your doctor can then have the muscle tissue analyzed by a pathologist to decide the next steps.

Your doctor might request a muscle biopsy to check for abnormalities in the musculoskeletal system. Certain diseases can cause muscle pain or weakness. If you have these symptoms, a muscle biopsy can help your doctor figure out the cause.

Muscle biopsies can help diagnose diseases related to problems with the nervous system, connective tissue, or vascular systems. Diseases that your doctor can diagnose by looking at muscle tissue include:

Your doctor will most likely ask for a muscle biopsy after looking at blood tests and performing a physical exam. They may also perform an electromyogram (EMG), which is a way to test your muscle response, before a muscle biopsy. The results of your bloodwork, EMG, and physical exam help your doctor determine if a muscle biopsy can help diagnose a neuromuscular disease.

There are two kinds of muscle biopsies: open and needle. A needle biopsy uses a large needle to take out a piece of muscle tissue. If a larger area needs to be sampled, an open biopsy will be performed. In this procedure, a small incision is made in your skin and the muscle tissue is taken out from there.

Before your muscle biopsy. Before the procedure, your doctor will explain to you what happens during a muscle biopsy. They will ask you to sign a consent form and check to make sure you’re in good health. During this time, you can ask your doctor any questions you have. You should also tell them about any medications that you’re taking.

During the biopsy. A muscle biopsy is an outpatient procedure, so there’s no stay in the hospital. Your doctor will give you an anesthetic so that you don’t feel any pain in the area where the tissue is being removed.

You’ll be asked to lie on a table while the area that is being biopsied is cleaned. Next, your doctor will give you a local anesthetic to numb the area. They will then either perform an open biopsy or a needle biopsy. In the case of an open biopsy, your doctor will stitch up the biopsy site. In both cases, a bandage will be applied to keep the area clean. Your doctor will then send off the sample of muscle tissue to be analyzed in a lab.

You shouldn’t feel any pain during a muscle biopsy. Some people might feel a tugging sensation as the muscle tissue is being removed. This feeling may be more intense during an open biopsy than during a needle biopsy.

In most cases, the muscle tissue sample is taken from the thigh muscle, called the quadriceps. Depending on the disease, a different muscle group may be biopsied.

After your biopsy, you can usually go home right away. You’ll need someone to drive you home. Once you get home, you should rest the biopsied muscle for a day or two, and make sure that you keep the biopsy site clean and dry so that it can heal properly.

The biopsy area may be sore for a few days. If you need to, you can take a pain reliever to help with the pain, as long as your doctor says that it’s OK. Because a muscle biopsy is a fairly simple procedure, you should be able to return to your normal routine within a couple of days.

In the days following your procedure, you should contact your doctor immediately if you notice any of the following:

  • Fever
  • Redness, swelling, drainage, or bleeding around the biopsy area
  • Pain around the biopsy area that gets worse

Your lab results can take anywhere from 1 to 4 weeks to process. During this time, the muscle tissue sample is looked at under a microscope and analyzed. Different tests will be done on the sample to help determine the cause of your symptoms. A detailed report is then sent to your doctor, who’ll then talk to you about the results.

Even though a muscle biopsy is a simple procedure, there are still risks, as with any surgery. Some possible complications you should look for include:

  • Bruising and pain around the biopsy area
  • Lingering bleeding in the biopsy area
  • Infection in the biopsy area

There may also be specific risks related to your medical condition. Your doctor will discuss these with you.