Biochemical indices in synovial fluid as diagnostic tools in arthritis

ABSTRACT

Since analysis of synovial fluid, have a prime importance in the evaluation of inflammatory joint, samples of synovial fluid were obtained from the knee joints of patients with rheumatoid arthritis [13] and osteoarthritis [10]. Sera were obtained from patients and normal controls [15]. The concentrations of glucose, total protein [TP] and total sialic acid [TSA] and activity levels of lactate dehydrogenase [LDH], adenosine deaminase [ADA] and acid phosphatase [ACP] were determined in both the serum and synovial fluid. Serum TSA, LDH, ADA and ACP levels were significantly higher in rheumatoid arthritis than the normal controls [P < 0.05, P < 0.05, P < 0.05 and P < 0.001 respectively], whereas in osteoarthritis, only the mean sera LDH and ACP activities were significantly higher [P < 0.05 and P < 0.01 respectively]. There were no significant differences in serum glucose and TP levels. The synovial fluid TSA levels as well as ADAand ACP activities were significantly higher in rheumatoid arthritis group as compared to osteoarthritic group [P < 0.05, P < 0.01 and P < 0.05 respectively]. The synovial fluid glucose, TP levels and LDH activity did not significantly differ although the TP and LDH tend to have higher levels in rheumatoid arthritis. In addition, total and differential leucocytic count were performed. There was a significantly higher total leucocyte count [P< 0.01] and polymorphnuclear leucocyte percentage [P < 0.001] and a significantly lower lymphocyte percentage [P < 0.05] in the synovial fluid of the rheumatoid arthritis in comparison to osteoarthrilis. Positive significant correlations were found between synovial fluid LDH and TP and LDH and ACP and between serum TP and TSA in patients with rheumatoid arthritis. Analysis of synovial fluid especially total and differential leucocytic count, TSA, ADA and ACP activities are important in differential diagnosis of the two types of arthritis, distinguishing between inflammatory and non-inflammatory disorders