How is the breath test performed?

The “blowing test” generally refers to pulmonary function testing. During the test, the examinee wears a nose clip and places the mouthpiece in their mouth, then performs exhalation maneuvers as instructed by the physician. A spirometer measures specific parameters, and the physician interprets the results in conjunction with the examinee’s clinical symptoms to assess whether pulmonary function is abnormal. The procedure is as follows:

1. After the examinee assumes a seated position, the physician applies a nose clip and instructs them to breathe exclusively through the mouth.

2. The examinee opens their mouth and seals it around the spirometer’s mouthpiece, then exhales forcefully until no further air can be expelled, holding the final exhalation for 3 seconds.

3. After a brief rest, the examinee must immediately perform another forceful exhalation for 12 seconds, followed by a return to normal, relaxed breathing.

4. Upon completion of the test and after the physician has rendered a diagnosis, the examinee may leave independently.