Abstract:Objective To analyze the diagnostic value of pleural fluid lactate dehydrogenase (LDH), adenosine deaminase (ADA), total protein (TP), LDH/ADA ratio, and ADA/TP ratio in tuberculous empyema (TE).Methods This retrospective study included 102 empyema patients (January 2017 to December 2024) categorized into TE (n = 40) and nontuberculous empyema (NTE, n = 62) groups. Pleural fluid biochemical parameters (LDH, ADA, TP) and ratios were analyzed. Multivariate logistic regression and ROC curves were used to assess diagnostic performance.Results TE group had higher TP (P < 0.05) but lower LDH and LDH/ADA ratio (P < 0.05) than NTE group. Multivariate analysis identified TP (O^R = 1.132, 95% CI: 1.041, 1.230) and LDH/ADA ratio (O^R = 0.882, 95% CI: 0.810, 0.960) as TE predictors. ROC analysis showed TP (AUC = 0.758, sensitivity = 85.00%, specificity = 67.74%) and LDH/ADA (AUC = 0.764, sensitivity = 82.50%, specificity = 62.90%) outperformed other markers.Conclusion TP and LDH/ADA ratio are robust diagnostic markers for TE, aiding clinical differentiation from NTE.