1 Ask the subject for a detailed medical history, smoking history, and recent medications to exclude contraindications to pulmonary function testing, such as recent hemoptysis, recent angina pectoris or myocardial infarction, severe cardiac dysfunction, heart rate >120 beats/min, pneumothorax or susceptibility to pneumothorax, severe pulmonary alveoli, and severe hypertension. Zhang Shaofu, Department of Respiratory Medicine, Shandong Qianfo Mountain Hospital, Shandong Province, China.2 To obtain an accurate estimate of the subject’s pulmonary function, the subject’s height and weight should be measured with shoes removed and lightly clothed.3 The subject should be given a detailed explanation of the test procedure and precautions to ensure that he or she understands why good cooperation is required.4 The instructor should demonstrate and show the test, using body language or cues such as pressing the subject’s shoulder with his or her hand to help the subject breathe. 5 Continuously prompt and encourage the subject during the test so that he or she can follow the instructor’s instructions to complete the forceful breathing maneuver.6 The spirometer should be calibrated with a calibrator each day when the machine is turned on.