What is Cell Count - Synovial fluid?
Also Known As:
Joint Fluid Analysis, Joint Fluid Aspiration, Arthrocentesis
Synovial fluid analysis is a group of tests that detect changes in synovial fluid. Synovial fluid is the liquid that surrounds and lubricates joints. When patients have swollen, painful joints, a synovial fluid analysis can give valuable information about the underlying source of the problem.
A number of tests can be conducted on synovial fluid after it is extracted from the joint space during a procedure called arthrocentesis. The appearance of synovial fluid, as well as its chemical properties, microscopic composition, and other signs of infectious disease may be analyzed.
The purpose of a synovial fluid analysis is to evaluate the cause of joint pain and inflammation. A synovial fluid analysis can help doctors narrow down or diagnose one of the many potential causes of joint pain. A synovial fluid analysis may be ordered to diagnose or rule out the following conditions:
- Autoimmune disorders: Autoimmune disorders are conditions in which a person’s immune system mistakenly attacks healthy tissue. In some autoimmune disorders, including rheumatoid arthritis, lupus, and psoriatic arthritis, the immune system damages healthy tissues of the joints.
- Septic arthritis: Septic arthritis is an infection caused by microbes such as bacteria or fungi that lead to acute inflammation in one or more joints.
- Gout or pseudogout: Gout and pseudogout are painful forms of arthritis, caused by the accumulation of uric acid or calcium crystals in the joint.
- Bleeding in the joint: Also called hemarthrosis, an accumulation of blood in the joint can be caused by an injury to the joint, cancer, hemophilia, and other health conditions.
What does the test measure?
Synovial fluid analysis can consist of several tests which may be performed on the fluid extracted from the joint. Broadly, the tests conducted as part of the synovial fluid analysis fall into three categories: gross assessment, chemical analysis, and microscopic assessment.
A gross assessment of synovial fluid describes the process in which a doctor examines the synovial fluid for characteristics such as volume, clarity, color, and viscosity. A gross assessment can help doctors begin to understand the cause of a patient’s symptoms.
A microscopic assessment of synovial fluid includes several tests to further evaluate a patient’s symptoms. During a microscopic assessment, the synovial fluid is examined using a microscope with a special filter to detect the presence of crystals, called a crystal analysis. If crystals are detected in the synovial fluid, their structure and composition can provide additional support for certain diagnoses.
When should I get synovial fluid analysis?
A synovial fluid analysis may be ordered by your doctor in a number of situations where the cause of joint problems is unknown. The following symptoms may indicate the need for a synovial fluid analysis:
- Joint swelling often referred to as joint effusion
- Sudden pain and warmth in a joint
- Redness at a joint
- Difficulty bending a joint
- Joint discomfort accompanied by fever
Joint fluid analysis is not performed as often in children with joint swelling and pain unless they have symptoms that suggest a joint infection, such as fever and the appearance of being very ill.
Your doctor can tell you how synovial fluid analysis can confirm or rule out diseases that may be causing your symptoms. They can also explain why the benefits of testing outweigh the small risks involved with the procedure.
How to get tested
Synovial fluid analysis is ordered by a doctor. The test may be ordered by your primary care provider, a specialist such as a rheumatologist, who specializes in treating joint diseases, or an orthopedist or orthopedic surgeon, who specializes in bone and connective tissue disorders.
Synovial fluid analysis is conducted on joint fluid, which is extracted from the joint through a procedure called arthrocentesis. Arthrocentesis is typically performed in the office of the provider who orders the test, or in another medical setting, like a hospital. Arthrocentesis is administered by a medical professional who has been trained in the procedure, such as a physician, physician’s assistant, or nurse practitioner.
Can I take the test at home?
Synovial fluid analysis cannot be conducted at home. The process by which joint fluid is removed, arthrocentesis, is only performed in a professional medical setting.