The sputum test for pulmonary tuberculosis, if Mycobacterium tuberculosis can be detected, is an important condition to confirm the diagnosis of active pulmonary tuberculosis, whether the sputum specimen is qualified is very important to determine the positive rate of the sputum test, so the sputum specimen should be taken with the following aspects: 1. Rinse the mouth with water before taking the sputum specimen to remove the food residue in the mouth. 2. The sputum volume should not be less than 3mL. 3. If there is no sputum, use concentrated saline to stimulate sputum excretion, do not retain saliva or nasopharyngeal secretions, so that the positive rate of detection of Mycobacterium tuberculosis is very low, affecting the doctor’s judgment and correct treatment. 4.