Clinical significance of the combined assay of pleural fluid ADA activity and CEA level in the various pleural effusion.

Background: In order to establish the etiology of the pleural effusion, routine analysis of the fluid , bacteriologic studies, cytologic tests and pleural biopsies are currently being employed.However, even with the above mentioned tests, the exact causes cannot be determined in approximately 10 -20% of cases.The purpose of our study is to determine the diagnostic value of measuring ADA activity and CEA simultaneously in various pleural fluids which their etiologies have confirmed.Methods: We have studied 61 cases of tuberculous pleural effusions, 17 cases of suspected tubercu.lous pleural effusions, 17 cases of malignant pleural effusions, 22 cases of suspected malignant pleural effusions, and 7 cases of parapneumonic pleural effusions.We have measured the ADA activity and CEA level simultaneously in pleural fluid samples in each cases.Results:1) The ADA activity in tuberculous pleural effusion was significantl y higher than that in malignant effusion2) The CEA level in malignant pleural effusion was significantly higher tha n that in tuberculous effusion 3) With the cut.offvalues of the pleural fluid ADA activity more than 40 U/ L and the CEA level less than 12 ng/ mL, the sensitivity was 86 .9% , and the specificity was 100% in the diagnosis of tuberculous effusion.With the cut.offvalues of the pleural fluid CEA level more than 12 g/ mL and the ADA activity less than 40 U/ L, the sensitivity was 76.5% , and the specificity was 100 % in the diagnosis of malignant effusion.Conclusion: It is suggested that the combined assay of pleural fluid ADA activity and CEA level is very useful in the differential diagnosis of tuberculous and malignant pleural effusion