Final answer:
A thoracentesis is performed to obtain pleural fluid for diagnostic purposes, usually when pleural effusion is suspected, but carries potential risks such as pneumothorax, infection, bleeding, or injury.
Step-by-step explanation:
A thoracentesis is a diagnostic procedure used to acquire pleural fluid for analysis, typically in cases of suspected pleural effusion. While it can provide valuable information for diagnosis, the procedure does carry certain risks. Complications may include pneumothorax (air in the chest cavity that can collapse the lung), infection, bleeding, or injury to the lung or other nearby structures. It is important that the procedure is carried out by a skilled clinician to minimize these risks.