Sputum examination is a non-invasive test and the time for results is related to the specific items examined. Sputum examination specimens are easier to obtain and are non-invasive, and the time to produce results is related to the specific items examined. Sputum smear examination requires a series of operations such as smearing and fixation to make a cytological smear, which is observed under a microscope to determine whether there are abnormal cells such as tumor cells and inflammatory cells, and the results are usually available within 1 day. If respiratory tract infection is considered, sputum culture is needed to clarify the pathogenic bacteria. The results of ordinary bacterial culture usually come out in about 1 week, and the specific time is related to the pathogenic bacteria, while special bacterial culture takes a little longer, sputum Mycobacterium tuberculosis culture takes 6-8 weeks, and sputum culture should be kept for 3 consecutive times to increase the accuracy of detection. The sputum should be collected early in the morning after the patient wakes up, rinses his mouth with water, coughs up the deep sputum, and puts it in a closed specimen bottle for examination, paying attention to prevent the contamination of the specimen by saliva and upper respiratory secretions.