Laboratory evaluation and interpretation of synovial fluid.

Canine and feline joint disease can be a primary disorder limited to joints or a manifestation of multisystemic disease. Collection and analysis of joint fluid provides valuable information for the diagnosis, prognosis, and treatment of diseases that affect the joint space. The cytologic recognition of the cellular components and infectious agents in synovial fluid categorizes the cell response and differentiates inflammatory and noninflammatory joint disorders. This information is supported by the cell counts, protein content, mucin clot test, bacterial culture, and serologic tests for infectious or immune-mediated disease. These results are integrated with the clinical history, physical examination, radiographic findings, and ancillary test results to arrive at a diagnosis and treatment plan.