Synovial fluid analysis

How the test is performed:

Normal synovial fluid is a clear or pale-yellow fluid found in small amounts in joints, bursae, and tendon sheaths. To obtain the fluid for analysis, a sterile needle is inserted into the joint space. In the laboratory, the fluid is analyzed for color, clarity, quantity, and other factors. It is examined microscopically for formed elements (such as cells), bacteria, and chemical analysis.

How to prepare for the test:

Fasting 6 to 12 hours before the test is sometimes required if glucose is to be analyzed. You must sign a consent form.

Infants and children:
The physical and psychological preparation you can provide for this or any test or procedure depends on your child's age, interests, previous experience, and level of trust. For specific information regarding how you can prepare your child, see the following topics as they correspond to your child's age:

• infant test or procedure preparation (birth to 1 year)
• toddler test or procedure preparation (1 to 3 years)
• preschooler test or procedure preparation (3 to 6 years)
• schoolage test or procedure preparation (6 to 12 years)
• adolescent test or procedure preparation (12 to 18 years)

How the test will feel:

You will be given local anesthesia. There is usually transient pain when the needle enters the joint capsule.

Why the test is performed:

The test is performed to identify the cause of swelling in the joints, to diagnose certain types of arthritis and inflammatory joint diseases, and to relieve pain and distention from fluid accumulation in the joint.