Definition of Synovial biopsy:

A synovial biopsy is the removal of a piece of tissue lining a joint. The tissue is called the synovial membrane.

How the test is performed:

The test is usually done in the operating room with the use of arthroscopy.

The health care provider will inject a numbing medicine (local anesthetic) into the area. An instrument called a trocar is inserted into the joint space. This tool helps push fluid in and out of the area. A biopsy grasper is inserted through the trocar and turned to cut out a tissue segment.

The tools are removed. The biopsy site is cleaned. Pressure and a bandage are applied.

How to prepare for the test:

Tell your health care provider:

• If you are pregnant
• If you have any drug allergies
• If you have bleeding problems
• What medications you are taking (including any herbal medicines and supplements)

How the test will feel:

With the local anesthetic, you will feel a prick and a burning sensation. As the trocar is inserted, there will be some discomfort.

Why the test is performed:

Synovial biopsy helps diagnose gout, bacterial infections, or other infections, and may suggest the presence of inflammatory conditions such as autoimmune disorders.

Normal Values:

The synovial membrane structure is normal.

What abnormal results mean:

Synovial biopsy may identify the following conditions:

• Coccidioidomycosis (a fungal infection)
• Fungal arthritis
• Gout
• Hemochromatosis (abnormal accumulation of iron deposits)
• Tuberculosis
• Synovial cancer

The test may help diagnose rheumatoid arthritis and other autoimmune diseases.

What the risks are:

There is a very slight chance of infection and bleeding. Rarely, there is a chance of the needle striking a nerve or blood vessel.