The common tests for respiratory diseases are broadly divided into laboratory tests and special tests. Laboratory tests 1. Routine blood tests: check for anemia or erythrocytosis. Leukocytosis suggests bacterial infection; normal or reduced white blood cells are common in tuberculosis or viral infections; eosinophilia often suggests the presence of allergic factors. Serological tests can help in the diagnosis of viral infections. 2, sputum and pleural fluid examination: the most important experimental diagnosis of respiratory system diseases is the examination of sputum and pleural fluid. Sputum examination methods include direct smear examination, sputum culture and animal inoculation. Pleural effusion examination can distinguish between leaking and exuding fluid, which is helpful in further determining the etiology. The examination of exfoliated cells in sputum and pleural effusion is also more helpful for the diagnosis of tumor. 3.X-ray examination: chest X-ray, radiography and tomography are important diagnostic bases for respiratory system diseases. Body layer radiography with fluorescence fluoroscopy can directly observe the obscured part, and can do dynamic observation, such as cardiovascular and diaphragm activity. In recent years, high-voltage and tomographic examinations are of great help in the diagnosis of thoracic tumors and other diseases, but they are of little help in bronchial diseases and need to be combined with physical examination to assist in the diagnosis. Special examination 1.Bronchoscopy: fiberoptic bronchoscopy is very helpful for the diagnosis of central bronchial lung cancer and bronchial endothelial tuberculosis, which can directly peer into the tumor, clip or brush biopsy, and also aspirate secretions for exfoliative cell examination. 2.Iodine oil bronchography: It can be used to observe bronchial morphology, which is helpful for the diagnosis of bronchial dilatation and bronchial tumor. However, this test is more painful and has certain danger. Nowadays, tantalum powder is mostly used for nebulization, but the degree of shadowing is not as clear as iodine oil or barium. 3.Diagnostic artificial pneumothorax or pneumoperitoneum: it can observe the morphological changes of lung, pleura or diaphragm to determine the location of intrathoracic tumor. 4.Lymph node biopsy: taking lymph node biopsy from supraclavicular or axillary etc. can help to diagnose thoracic tumor. 5.Radioisotope lung scan: It is used to diagnose intra-pulmonary vascular lesions (such as pulmonary infarction) with good effect. 6.Respiratory function tests: usually include respiratory volume measurement, respiratory tracing pulmonary function analysis, blood gas analysis, whole body volume tracing, etc. These tests are of great significance for the early diagnosis of chronic respiratory obstructive diseases and respiratory function measurement.