[Diagnostic usefulness of neurospecific enolase determination in pleural fluid]

To investigate the diagnostic usefulness of the measurement of neurospecific enolase (NSE) in pleural fluid 116 consecutive patients with pleural effusion were prospectively evaluated. In 95 of them, carcinoembryonic antigen (CEA) was also measured for comparative purposes. The habit of smoking did not apparently influence the NSE levels. In the 43 malignant effusions the mean value of NSE (25.0 +/- 27.4) was significantly higher (p less than 0.001) than in benign effusions (8.7 +/- 7.1). The values above 12 ng/ml had a sensitivity of 51% for malignancy, with a specificity of only 74%. The specific sensitivity of NSE was lower than that of CEA; neither individually nor as a whole these markers modified the diagnostic yield of cytology (67%). The mean value of NSE in tuberculous pleural effusions (14.4 +/- 8.3), different from that found in malignancies (p less than 0.05), was significantly higher (p less than 0.001) than that found in other benign diseases (6.2 +/- 4.7). The results of this study demonstrate the nonspecific character of an increased level of NSE, and the low diagnostic yield of this enzyme as a pleural tumour marker.