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

The test may be done in your health care provider's office. The joint to be biopsied will be positioned precisely so the doctor can easily reach it.

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 out of the area. A biopsy needle is inserted through the trocar and turned to cut out a tissue segment.

The tools are removed. The biopsy site is cleaned, and pressure and bandage are applied.

This procedure may also be performed in a hospital using arthroscopy.

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)

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

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

The synovial membrane structure is normal.

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.

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