The case against performing pleural biopsies for the aetiological diagnosis of exudates.

In most cases, the etiological diagnosis of pleural exudates does not require a pleural biopsy. However, when it is considered necessary, the biopsy should seldom be conducted using invasive methods such as thoracoscopy. Two paradigmatic examples are pleural tuberculosis and malignant effusions. In many centres, pleural fluid adenosine deaminase measurement has replaced closed pleural biopsies in the diagnosis of tuberculosis. Similarly, pathological and molecular studies on pleural fluid cell blocks or alternatively, image-guided pleural biopsies have drastically reduced the need for thoracoscopy.