Differences in pleural fluid characteristics, white cell count and biochemistry of tuberculous and malignant pleural effusions.

Tuberculosis and malignancy are two common causes of exudative pleural effusions. In this retrospective study of 52 patients with tuberculous pleural effusions and 32 patients with malignant effusions, the median age of patients with malignant effusions (68.5 years) was older than that of patients with tuberculous effusions (34.5 years) (p < 0.001). Both types of effusion occurred more frequently on the right side and there was no difference between them in terms of right-sided dominance. A higher percentage of patients with malignant pleural effusions (44%) presented with large effusions than patients with tuberculous effusions (12%) (x2 = 11.33, p = 0.001). A higher proportion of patients with tuberculous effusion had lymphocyte predominant effusions and tuberculous effusions had higher lymphocyte percentage, lower red cell count, and higher protein content. However, there was considerable overlap of these characteristics of both types of effusions.