Joint fluid analysis
Joint fluid analysis is a procedure used to assess joint-related abnormalities, such as
in the knee or elbow.
Why is a joint fluid analysis performed?
A joint fluid analysis is performed to identify the cause of swelling in the joints, to
relieve pain and distention from fluid accumulation in the joint, and to diagnose
certain types of arthritis and inflammatory joint diseases. The test is also a method to
determine whether an infection, either bacterial or fungal, exists within the joint.
How a joint fluid analysis is performed
This procedure is done by passing a needle into a joint space and sucking out
(aspirating) synovial fluid for diagnostic analysis. When the sample is sent to the
laboratory, the fluid is analyzed for color, clarity, quantity, and chemical composition.
It is also examined microscopically to check for the presence of bacteria and other cells.
The patient is asked to lie on their back and remain relaxed. The local anesthetic,
typically an injection of lidocaine, is then administered. The clinician is usually seated
next to the patient. Then the clinician marks exactly where the needle is to enter. As the
needle enters the joint, a "pop" may be felt or heard. This is normal. Correct
placement of the needle in the joint space is normally painless. At this point, the
clinician slowly drains some of the fluid into the syringe. The needle is then withdrawn
and adhesive tape is placed over the needle site. |
