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Crystal Identification Synovial Fluid Test

Last updated June 11, 2019

Approved by: Krish Tangella MD, MBA, FCAP

The Crystal Identification Synovial Fluid Test detects crystals in synovial fluid that may be caused by a variety of joint disorders.

What are other Names for this Test? (Equivalent Terms)

  • Crystal Identification Joint Fluid Test

What is Crystal Identification Synovial Fluid Test? (Background Information)

  • Synovial fluid is a thick substance found in the major joints (shoulder, hip, elbow, wrist, knee, and ankle), most notably in the knee. It acts as a lubricant, shock absorber, and nutrient medium
  • The joints link the ends of bones together and enable them to articulate, or move against one another. However, bones do not contact each other as this would cause degradation and pain
  • Instead, the articular surfaces of bones are covered by articular cartilage. This is a smooth form of cartilage that is less dense, and thus slicker, than other cartilages
  • The synovial fluid fills the spaces between articular surfaces within the joints. Articular cartilage is also permeable to synovial fluid, which enables the two to work together to provide further joint protection
  • When articular cartilage is compressed, it pushes the synovial fluid out and into the joint, where the fluid can lubricate the opposing surfaces. When compression is relieved, the fluid reenters the articular cartilage
  • Similarly, synovial fluid acts as a shock absorber. The forces felt by the joints are spread across synovial fluid, lessening stress on the articular surfaces
  • Another important function of synovial fluid is to exchange wastes and nutrients with the surrounding capillaries. This allows for proper maintenance of the joint tissue
  • Joint disorders are categorized into 5 groups: Non-inflammatory, inflammatory, crystal-induced, septic, and hemorrhagic
  • The Crystal Identification Synovial Fluid Test detects crystals in synovial fluid that may be caused by a variety of joint disorders

What are the Clinical Indications for performing the Crystal Identification Synovial Fluid Test?

Following are the clinical indications for performing the Crystal Identification Synovial Fluid Test:

  • Following-up to a physical examination
  • Monitoring of a joint disorder
  • Recent injury
  • Swelling
  • Redness
  • Pain

How is the Specimen Collected for Crystal Identification Synovial Fluid Test?

Following is the specimen collection process for Crystal Identification Synovial Fluid Test:

Sample required: Synovial fluid

Process of obtaining a synovial fluid sample (arthrocentesis) in adults:

  • Cleaning the body site with 70% alcohol
  • Insertion of a needle into the site
  • Collection of synovial fluid into the collection container of the syringe
  • Removal of the needle

Preparation required: No special preparation is needed prior to the test.

What is the Significance of the Crystal Identification Synovial Fluid Test Result?

A positive value for the Crystal Identification Synovial Fluid Test may indicate:

  • Gout
  • Pseudogout
  • Long-term renal dialysis
  • Joint degeneration
  • Eosinophilic synovitis

The laboratory test results are NOT to be interpreted as results of a "stand-alone" test. The test results have to be interpreted after correlating with suitable clinical findings and additional supplemental tests/information. Your healthcare providers will explain the meaning of your tests results, based on the overall clinical scenario.

Additional and Relevant Useful Information:

  • After collection, synovial fluid may be analyzed for appearance, chemistry, and the presence of cells via the synovial fluid analysis test

Certain medications that you may be currently taking may influence the outcome of the test. Hence, it is important to inform your healthcare provider of the complete list of medications (including any herbal supplements) you are currently taking. This will help the healthcare provider interpret your test results more accurately and avoid unnecessary chances of a misdiagnosis.

The following DoveMed website links are useful resources for additional information: 





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References and Information Sources used for the Article:

Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: Jan. 13, 2016
Last updated: June 11, 2019