Abstract: Objective: To explore the clinical significance of the joint detection of carbohydrate antigen 125(CA125) and adenosine deaminase(ADA) in hydrothorax in the diagnosis of tuberculous pleurisy.Methods: The levels of CA125 and ADA in hydrothorax of 54 patients with tuberculous pleurisy and 40 patients with malignant pleural effusion were measured using electrochemiluminescence assay.The four tumor markers(including carcino embryonic antigen,CA199,neuron-specific enolase,cylokerain fragments21-1 were also detected.Results: The concentrations of CA125 and ADA in hydrothorax of tuberculous pleurisy were(702.67 ± 367.30)u/ml and(81.74±18.82)u/L,respectively,whose were higher than the normal level.The sensitivity of CA125(100.0%) was higher than that of ADA(88.9%) in hydrothorax.The positive rates of four tumor markers were low.The sensitivity and specificity of the joint detection of CA125 and ADA could be increased to 88.9% and 90.75%,respectively.Conclusions: The measurement of CA125 is beneficial in the diagnosis of tuberculous pleurisy.The combined detection of CA125 and ADA can improve the diagnostic positive rate of tuberculous pleurisy,combined other tumor indexes detection can help to exclude malignant pleural effusion.