Synovial Fluid Analysis
synovial fluid analysis, also called synovial fluid analysis, is
a battery of tests performed on synovial (joint) fluid to help diagnose and treat
How the test is performed
To obtain the fluid for analysis, a sterile needle is inserted
into the joint space through skin that has been specially cleaned. Once in the joint,
fluid is aspirated through the needle into a sterile syringe.
Synovial fluid is normally a viscous (thick), straw colored substance found in small
amounts in joints, bursae, and tendon sheaths. In the laboratory, the fluid is initially
analyzed for color and clarity. It is then examined microscopically for cells (red and
white cells), crystals (in the case of gout), and bacteria. In addition, there may be a
chemical analysis, and if infection is a concern, a sample will be cultured to see if any
Abnormal joint fluid may look cloudy or abnormally thick
Precautions of synovial fluid analysis
synovial fluid analysis should not be performed on any patient who is uncooperative,
especially if the patient cannot or will not keep the joint immobile throughout the
procedure. Patients with certain infections should be excluded from the procedure,
particularly those who have a local infection along the proposed needle track. The joint
space should be accessible. Therefore, a poorly accessible joint space, such as in hip
aspiration in an obese patient, should not be subject to this procedure.
Preparation for synovial fluid analysis
Glucose, or sugar, in the joint can be a signal of arthritis. If the clinician will be
doing a glucose test, the patient will be asked to fast for 6-12 hours preceding the
procedure. If not, there is no special preparation required for a synovial fluid
Aftercare of synovial fluid analysis
Some post-procedural pain may be experienced. For this reason, the patient should
arrange to be driven home by someone else. Aftercare of the joints will depend on the
results of the analysis.
Risks of synovial fluid analysis
While synovial fluid analysis is generally a safe procedure, especially when
performed on a large, easily accessible joint, such as the knee, some risks are possible.
Some of the complications to the procedure, although rare, include infection at the site
of the needle stick, an accumulation of blood (hematoma) formation, local pain, injury to
cartilage, tendon rupture, and nerve damage.
Normal results of synovial fluid analysis
The results of a normal synovial fluid analysis include fluid of a clear or
pale-yellow color and the absence of bacteria, fungus, and other cells, such as white
Abnormal results of synovial fluid analysis
The results of an abnormal synovial fluid analysis include fluid that is turbid,
or cloudy. Also, white blood cells and other blood cells may be found, from which the
clinician can make a diagnosis and arrive at a treatment for the joint problem. An
abnormal result can indicate an infection caused by a bacteria, or tuberculosis. Or, there
might be inflammation that is caused by gout, rheumatoid arthritis, or osteoarthritis.