Lupus Site - a guide for lupus patients and their families

Synovial fluid is a liquid found in small amounts within the joints. This liquid is produced by the membrane lining the capsule of a joint, known as the synovial membrane. During a joint aspiration, the synovial fluid is drawn out using a needle, and looked at under a microscope. A joint aspiration is done to help diagnose joint problems in a person with joint pain, swelling, or deformity.

Local anesthesia is injected into the joint to numb the area. The area is then cleaned with an antiseptic. A sterile needle is inserted into the joint space. A small amount of the synovial fluid is withdrawn and sent to the laboratory for analysis. The procedure usually takes about 10 minutes. The only discomfort usually occurs when the local anesthesia is injected.

Normal synovial fluid is clear and light tan in color.

Abnormal results may indicate:

• infection injury to the joint arthritis, or inflammation or swelling of a joint

• toxic synovitis, or inflammation of the synovial membrane

• a tumor or growth involving the joint

• increased fluid within the joint

• gout, which is a form of arthritis caused by deposit of uric acid crytals into the joint

• systemic lupus erythematosus