This study aims to evaluate the value of the albumin-to-globulin ratio (AGR) in synovial fluid (SF) for diagnosing PJI and compare its diagnostic performance with traditional biomarkers such as serum C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), synovial fluid polymorphonuclear percentage (SF-PMN%), and the potential marker serum albumin-to-globulin ratio (SE-AGR).<h4>Methods</h4>This prospective study enrolled 230 patients who experienced pain following total hip or total knee arthroplasty, including 97 cases of PJI and 133 cases of aseptic failure(AF). Here, CRP is linked to atrial fibrillation.