Diagnostic value of CA 72-4, carcinoembryonic antigen, GA 15-3, and CA 19-9 assay in pleural fluid - A study of 207 patients

BACKGROUND. The differential diagnosis of pleural effusion is a frequent clinical problem. Several tumor markers have been evaluated in pleural fluid, but the value of CA 72-4 assay and of combinations of tumor marker assays has not been firmly established. To find a minimally invasive tool for differentiating between pleural effusions of malignant or benign origin, the authors assessed the diagnostic value of CA 72-4, carcinoembryonic antigen (CEA), CA 15-3, and CA 19-9 assays in pleural fluid individually and in combination. METHODS. The authors prospectively studied 207 patients with pleural effusion (65 malignant, 48 tuberculous, 24 parapneumonic, 26 transudates, 14 miscellaneous; and 30 of unknown nonneoplastic origin). The levels of CA 72-4, CEA, CA 15-3, and CA 19-9 were measured in pleural fluid by radioimmunoassay. RESULTS. CA 72-4 assay in pleural fluid had an acceptable sensitivity and very good specificity for diagnosing malignant pleural effusion. The combination of CA 72-4 plus CEA plus CA 15-3 yielded the best accuracy, 0.90 (95% confidence interval [CI] 0.85-0.94), with a sensitivity of 0.78 (95% CI, 0.67-0.88), specificity of 0.95 (95% CI, 0.90-0.98), positive predictive value of 0.88 (95% CI, 0.77-0.95), and negative predictive value of 0.91 (range, 0.85-0.94). A good clinical strategy may be to begin with a CEA assay (specificity of 1) and then, if it is negative, to add CA 15-3 or even CA 72-4 assays to improve sensitivity. The diagnosis of mesothelioma is more likely with a high CA 15-3 level and normal CEA and CA 19-9 levels. CONCLUSIONS. Assays of CEA, CA 72-4, and CA 15-3 in pleural fluid, or the combination of CEA with CA 15-3 and CA 72-4, was useful in differentiating between pleural effusion of malignant and benign origin. (C) 1996 American Cancer Society.