ABSTRACT
OBJECTIVE: To investigate whether synovial fluid adenosine deaminase activity is useful in the differential diagnosis of joint swelling and in estimating the disease activity. METHOD: Adenosine deaminase activity was determined in the synovial fluid taken from patients with rheumatoid arthritis (n=21), osteoarthritis (n=ll), ankylosing spondylitis (n=3), and gouty arthritis (n=2). This enzyme activity was compared with the laboratory indices (ESR, CRP) in the blood and the other parameters in the synovial fluid. RESULT: More increased adenosine deaminase activity was found in the synovial fluid taken from patients with rheumatoid arthritis, ankylosing spondylitis, and gouty arthritis, as compared with that of osteoarthritis patients. Synovial fluid ADA activity was significantly corelated with the WBC count in the synovial fluid, but there was no statistical corelation between other synovial parameters and adenosine deaminase activity. CONCLUSION: Adenosine deaminase activity is useful in the differential diagnosis of joint swelling between inflammatory joint disease and osteoarthritis, but not useful in estimating the disease activity.