Could you tell me what happens when you get tested for asthma?

Breathing tests: The usual test for asthma is a breathing test called spirometry where a person blows into a machine. The person then takes some puffs of albuterol (asthma medication by inhaler) and the breathing test is repeated 20 minutes later. If the breathing improves by 12%, then this is consistent with asthma. For a new diagnosis, a chest x-ray may be done and if available, a Nitric Oxide breath test.