Diagnostic significance of cancer antigen 125, pancreatic oncofetal antigen, and carcinoembryonic antigen in malignant and tuberculous pleural effusions.

Pleural fluid levels of cancer antigen 125 (CA 125), pancreatic oncofetal antigen (POA), and carcinoembryonic antigen (CEA) were determined in 56 patients with malignant pleural effusion and in 35 patients with tuberculous effusion. Malignant effusions had significantly higher pleural fluid CA 125 and CEA levels than those of tuberculous origin (p less than 0.005). No significant difference in POA titers was found between the two kinds of effusion. Assays of CA 125 and CEA in pleural fluid may be useful in separating malignant from tuberculous effusions. Concurrent measurement of CA 125 and CEA proved superior to determination of CEA alone in discriminating between the two groups.