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 A small amount of the synovial fluid is withdrawn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