Approximately 1.5 million pleural effusions are diagnosed each year in the USA. Light’s Criteria are primarily used to categorize the effusions into exudates and transudates on biochemical grounds which can help ascertain the underlying etiology. Further biochemical, microbiologic, and histopathologic testing of the pleural fluid can allow for identification of a specific etiology. When exact etiology cannot be determined from pleural fluid analysis and review of history, clinical exam, and imaging, a pleural biopsy can be considered to rule out malignancy and identify other etiologies. This allows for appropriate disease directed treatment as well as optimal management of the pleural space in case there is recurrence after initial drainage. Patients who are diagnosed with nonspecific pleuritis should continue to be monitored with clinical and radiographic follow-up.