Carcinomatous and tuberculous pleural effusions. Comparison of tumor markers.

As an aid in the differential diagnosis of exudative pleural effusions, tumor markers were investigated. We measured immunosuppressive acidic protein (IAP), carbohydrate antigen 19-9 (CA 19-9), tissue polypeptide antigen (TPA), carcinoembryonic antigen (CEA), adenosine deaminase (ADA), and alpha 1-acid glycoprotein (AGP) in the pleural fluid of 36 patients with carcinomatous pleural effusions and of 35 patients with tuberculous pleurisy because we have frequently found these diseases to be associated with exudative pleuritis. Tuberculous pleural effusions had significantly higher levels of IAP, ADA, and AGP than carcinomatous effusions (p less than 0.005). On the other hand, CEA, CA 19-9, and TPA were significantly higher in carcinomatous pleural fluids than in tuberculous fluids (p less than 0.05). There was a correlation between IAP and AGP levels, and their specificity was low. Therefore, combined assays of CEA, CA 19-9, and ADA may be useful in distinguishing pleural effusions due to malignancies from those of tuberculous origin.