[Carcinoembryonic antigen in serum and pleural fluid to distinguish between bronchial carcinoma and pleural mesothelioma].

The concentrations of carcinoembryonic antigen (CEA) were measured, partly retrospectively and partly prospectively, in 94 patients with diffuse malignant mesothelioma and in 79 with bronchial carcinoma and pleural involvement. Serum concentrations were measured in all patients, pleural-fluid concentrations additionally in 53 patients of the former and 39 of the latter group. The concentrations were significantly higher in those with bronchial carcinoma (P less than 0.001). The two groups could be distinguished by serum concentrations, using 5.2 ng/ml as the limit, with a sensitivity of 68%, specificity of 98% and a predictive value of 96%. Measurement of CEA in pleural fluid (at a limit of 4.5 ng/ml) had a specificity of 94% and a positive predictive value of 90%, sensitivity being similar to that for serum. The negative predictive value for serum CEA concentration was 79%, for pleural fluid it was 81%. Thus in most cases measurement of CEA in serum and, to a lesser extent in pleural fluid, is a very simple method to exclude mesothelioma with a high degree of certainty. If the CEA concentration is below the stated level, either may be present.