Synovial fluid analysis is also known as joint fluid analysis. It
helps diagnose the cause of joint inflammation.
Each of the joints in the human body contains synovial fluid.
This fluid is a thick liquid that lubricates the joint and allows for ease of
movement. In joint diseases like arthritis, the synovium of the joint is the
main place where inflammation occurs.
Limited mobility in the joint, or pain and stiffness with
movement, are often the first signs of joint disorders. Synovial fluid and
joint inflammation are more common as you age.
Why Is the Test Done?
A synovial fluid analysis is performed when pain, inflammation,
or swelling occurs in a joint, or when there’s an accumulation of fluid with an
unknown cause. Taking a sample of the fluid can help diagnose the exact problem
causing the inflammation. If the cause of the joint swelling is known, a
synovial fluid analysis or joint aspiration may not be necessary.
Some potential diagnoses include infection, gout, arthritis, and
bleeding. In some cases with excess fluid, simply removing some fluid can help relieve
pain in the affected joint.
Sometimes synovial fluid analysis is used to monitor people with
known joint disorders.
What to Expect
A synovial fluid analysis may be mildly uncomfortable, but the
whole process lasts only a few minutes. You might receive a local anesthesia to
numb the area. You may feel a prick and burning sensation from the anesthesia
at the site of entry.
A larger needle will then be inserted into the joint to withdraw
the synovial fluid. If you receive anesthesia, you should feel minimal
discomfort. If you don’t receive anesthesia, the needle may cause slight pain
and discomfort. You might feel pain if the tip of the needle touches bone or a
Following the procedure, apply ice to reduce any pain or
Synovial Fluid Analysis Process
Your doctor will recommend a synovial fluid analysis if you have
signs of joint inflammation, redness, swelling, or injury to help diagnose the
You won’t need to do anything in preparation for the test, but
let your doctor know if you’re taking blood thinners. They can affect results.
The synovial biopsy process will be done at your doctor’s office.
This process doesn’t require any incisions, and will only take a couple of minutes.
Your doctor will clean the area and prepare it for injections. If you’re
getting anesthesia, your doctor will inject it into the site to limit pain and
Once the area has been numbed, your doctor will insert a larger
needle into the joint and draw fluid into the syringe. This process of removing
fluid from a joint is called arthrocentesis.
Your doctor will send the fluid sample to the laboratory for
examination. A lab technician will look at the color and thickness of the fluid
and assess red and white blood cells under a microscope.
The technician will also look for crystals or signs of bacteria
- uric acid
- lactic dehydrogenase (an enzyme that increases
in cases of inflammation and tissue damage)
The fluid sample will also be cultured to test for bacteria.
What Do the Test Results Mean?
Normal synovial fluid is straw-colored, clear, and slightly
sticky or stringy.
Abnormal synovial fluid may be cloudy and thicker or even thinner
than normal fluid. Cloudiness could
mean there are crystals, increased white blood cells, or microorganisms in the
If you have gout, the fluid will contain crystals. Less stringiness in the fluid
could signal inflammation. Excess
fluid in the joint could be a predictor of osteoarthritis. Reddish-colored fluid could mean
blood is present.
Blood in the fluid could
point to a bleeding injury in the joint or a more serious bleeding problem
throughout the body, such as hemophilia. Absent or ineffective clotting factors
Cloudy fluid, blood in
the fluid, or excess fluid are all signs of a problem in or around
the joint, such as:
- autoimmune disorders
- injury to the joint
This procedure is highly effective in diagnosing gout by
identifying crystals in the fluid.
The Risks of Synovial Fluid Analysis
A synovial fluid test carries minimal risks. The most common
risks are bleeding or infection in the joint. It’s normal to experience
soreness or stiffness in the joint. Complications from this procedure are rare.