Comparison of Alkaline phosphatase, Lactate Dehydrogenase and Acid Phosphatase Levels in Serum and Synovial Fluid between Patients with Rheumatoid Arthritis and Osteoarthritis

Introduction: Pain and swelling in joints is a fundamental feature of Rheumatoid Arthritis (RA),it is a chronic multisystem disease of unknown cause. Osteoarthritis (OA) has been characterized by progressive articular cartilage loss and osteophyte formation. Objective: Thisstudy was undertaken to evaluate whether it is possible to distinguish OA from RA by comparing LDH, ALP, Uric Acid and ACP levels within the synovial fluid and the serum. Materials and Methods: Thiswas a cross sectional study, total of 317 cases were included out of which 172 cases were already diagnosed cases of having OA and 145 cases were diagnosed with RA. Joint fluid was obtained by arthrocentesis from patients with clinical evidence of knee arthritis and joint effusion, blood samples were taken from the same patients. A combination of serological and aspiration analyses was done. Results: The mean levels of synovial LDH, ALP, ACP in RA patients were 474.23 ± 83.01 mg/dL,108.23 ± 54.43IU/L, 10.5±8.5 IU/L and in OA group were 311.86 ± 153.91 mg/dL,83.6 ± 15.0IU/L, 3.7±1.8 IU/L respectively, there was a statistically significant difference between them (p<0.0001). In RA patients, the synovial fluid levels of ALP with LDH (r=0.6549) showed direct and stronger correlation than the correlation between synovial fluid levels of ACP with LDH and ALP (r=0.4182 and r=0.4147) respectively. Conclusion: An assay for synovial fluid ALP, LDH and ACP levels may serve as a simple method for diagnosing and differentiating RA from OA in the future and this may allow for more targeted pharmaceutical and surgical intervention.