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.
A joint aspiration can be done in a doctor's office. 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 A small amount of the synovial fluid is withdrawn and sent to the laboratory for analysis.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.
The person may be asked to fast for 6 hours before the test. This is because food may interfere with the test results. For instance, the blood glucose level is normally lower in individuals who have arthritis.
Normal synovial fluid is clear and light tan in color. Abnormal results may indicate:
Author:Gail Hendrickson, RN, BS
Date Written:
Editor:Keefe, Sandy, RN, MSN
Edit Date:05/16/00
Reviewer:Barbara Mallari, RN, BSN, PHN
Date Reviewed:08/09/01
Mosby's Diagnostic and Laboratory Test Reference, Fouth Edition, 1999.