If a pleural effusion is found on physical examination and cannot be characterized, a thoracentesis must be performed to extract the effusion for examination. Patients may have no previous respiratory pathology, so routine chest X-ray and CT if necessary can be considered first. If the examination confirms a large amount of effusion, further ultrasound examination is done to locate the puncture site, which is performed after full communication with the patient and signing the informed consent for puncture. If the aspirated fluid is bloody, tumorigenic lesions need to be considered (especially in men over 40 years of age and long-term smokers) after ruling out inadvertent small vessel injury. However, about 10% of patients with tuberculous pleurisy can also have hemorrhagic effusions, and the differentiation needs to be judged by biochemistry, bacterial culture, and examination of tumor markers in the effusions, etc. If tuberculosis infection is suspected but never diagnosed, diagnostic treatment and multiple aspirations for bacterial examination can be done. Since the tuberculosis bacilli are present in the pleural effusion, patients who are negative for tuberculosis on sputum examination, chest CT and chest X-ray must have fluid aspiration to better identify the substance of the lesion.