Diagnostic Value of Carcinoembryonic Antigen (CEA) Assay in Pleural Effusions

Carcinoembryonic antigen (CEA) levels were evaluated by a direct radioimmunoassay in the effusion fluids and plasma samples from 107 patients with pleural effusions of unknown etiology. CEA levels higher than 20 ng/ml were detected in 55 % of pleural effusions from patients with malignant disease: 40 % of the patients in this group had values of plasmatic CEA lower than 20 ng/ml. With the only exception of 4 patients with empyema, CEA levels were uniformly lower than 20 ng/ml in the effusion fluid of patients with benign disease. Moreover, CEA levels higher than 20 ng/ml were observed in 81.2 % of pleural effusions and 31.2 % of plasma samples from patients with cytology positive for malignancy, whereas increased CEA levels were observed in 37.5 % of effusion fluids and 33.3 % of plasma samples from patients with malignant disease but negative cytology in the pleural effusion. CEA assay in the effusion fluid represents a useful tool of high specificity and good sensitivity to discriminate between benign and malignant etiology of pleural effusions.