Diagnostic value of carcinoembryonic antigen in pleural fluid.

ABSTRACT

A double antibody sandwich ELISA was used for the determination of carcinoembryonic antigen levels in sera and pleural fluid samples of 25 cancer and 16 tuberculous patients. It was found that while cancer patients had pleural fluid CEA levels significantly higher than those in sera (p < 0.01), this was not true for tuberculous patients. When the CEA level at 20 ng/ml was used as the cut-off value for the diagnosis of malignancies, 8 of 25 (32%) cancer patients could be diagnosed from serum CEA level while 16 of them (64%) could be diagnosed from CEA level in the pleural fluid. In addition, none of tuberculous patients had CEA above the cut-off level. Based on the results of cytologic examination, only 11 of the 25 cancer patients (44%) could be diagnosed. However, if either positive cytologic examination or pleural fluid CEA level higher than 20 ng/ml was used as a criterion for diagnosis, then 20 of them (80%) could be diagnosed.