Improvement of the diagnosis of the cause of pleural effusion in patients with lung cancer by simultaneous quantification of carcinoembryonic antigen (CEA) and neuron-specific enolase (NSE) pleural levels.

Carcinoembryonic antigen (CEA) and neuron-specific enolase (NSE) level determinations were carried out by radioimmunoassay in pleural fluid and plasma samples obtained from 24 patients with malignant pleural effusions and 18 patients with non-malignant pleural effusions, and compared to cytological and pathological results. Using a pathological cut-off level of 25 ng/ml for CEA and 8 ng/ml for NSE, we demonstrated that, in the diagnosis of the malignant nature of pleural effusions, the simultaneous quantification of CEA and NSE in pleural fluid possesses better discriminative values than the simultaneous quantification of both markers in plasma or the separate quantification of each marker, in pleural fluid and in plasma.