Health Library
Synovial fluid analysis
Joint fluid analysis; Joint fluid aspiration
Synovial fluid analysis is a group of tests that examine joint (synovial) fluid. The tests help diagnose and treat joint-related problems.
Images
I Would Like to Learn About:
How the Test is Performed
A sample of synovial fluid is needed for this test. Synovial fluid is normally a thick, straw-colored liquid found in small amounts in joints.
After the skin around the joint is cleaned, the health care provider inserts a sterile needle through the skin and into the joint space. Fluid is then drawn through the needle into a sterile syringe.
The fluid sample is sent to the laboratory. The laboratory technician:
- Checks the sample's color and how clear it is
- Places the sample under a microscope, counts the number of red and white blood cells, and looks for crystals (in the case of gout) or bacteria
- Measures glucose, protein, uric acid, and lactate dehydrogenase (LDH) levels
- Cultures the fluid to see if any bacteria grow
How to Prepare for the Test
Normally, no special preparation is needed. Tell your provider if you are taking a blood thinner, such as aspirin, warfarin (Coumadin), or clopidogrel (Plavix). These medicines can affect test results or your ability to have this test.
How the Test will Feel
Most often, the provider will first inject numbing medicine into the skin with a small needle, which will sting. A larger needle is then used to draw out the synovial fluid.
This test may also cause some discomfort if the tip of the needle touches bone. The procedure usually lasts less than 1 to 2 minutes. It may be longer if there is a large amount of fluid that needs to be removed.
Why the Test is Performed
The test can help diagnose the cause of pain, redness, or swelling in joints.
Sometimes, removing the fluid can also help relieve joint pain.
This test may be used when your provider suspects:
- Bleeding in the joint after a joint injury
- Gout, other types of crystal disease, and arthritis
- Infection in a joint
What Abnormal Results Mean
Abnormal joint fluid may look cloudy or abnormally thick.
The following found in joint fluid can be a sign of a health problem:
- Blood -- injury in the joint or bleeding problem of the body
- Pus -- infection in the joint
- Too much joint fluid -- osteoarthritis or cartilage, ligament, or meniscus injury
- Evidence of gout or pseudogout -- inflammatory conditions that can be treated with medicines
Risks
Risks of this test include:
- Infection of the joint -- unusual, but more common with repeated aspirations
- Bleeding into the joint space
Considerations
Ice or cold packs may be applied to the joint for 24 to 36 hours after the test to reduce the swelling and joint pain. Depending on the exact problem, you can probably resume your normal activities after the procedure. Talk to your provider to determine what activity is most appropriate for you.
References
El-Gabalawy HS, Tanner S. Synovial fluid analyses, synovial biopsy, and synovial pathology. In: Firestein GS, Budd RC, Gabriel SE, McInnes IB, O'Dell JR, eds. Firestein & Kelley's Textbook of Rheumatology. 11th ed. Philadelphia, PA: Elsevier; 2021:chap 56.
Pisetsky DS. Laboratory testing in the rheumatic diseases. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 242.
BACK TO TOPReview Date: 4/24/2023
Reviewed By: C. Benjamin Ma, MD, Professor, Chief, Sports Medicine and Shoulder Service, UCSF Department of Orthopaedic Surgery, San Francisco, CA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
 | A.D.A.M., Inc. is accredited by URAC, for Health Content Provider (www.urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M. follows rigorous standards of quality and accountability. A.D.A.M. is among the first to achieve this important distinction for online health information and services. Learn more about A.D.A.M.'s editorial policy, editorial process and privacy policy. A.D.A.M. is also a founding member of Hi-Ethics. This site complies with the HONcode standard for trustworthy health information: verify here. |
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. No warranty of any kind, either expressed or implied, is made as to the accuracy, reliability, timeliness, or correctness of any translations made by a third-party service of the information provided herein into any other language. © 1997- 2024 A.D.A.M., a business unit of Ebix, Inc. Any duplication or distribution of the information contained herein is strictly prohibited.
