2. Use at-home lung tests

Your health care team may ask you to use a device that measures how well your lungs are working. This is called a lung function test.

Your asthma action plan includes instructions for when or how often you should do a lung function test. The plan also tells you what to do if the test shows your lungs aren't working well.

You may use one of these devices:

• Peak flow meter. This device measures how quickly you can force air out of your lungs. Peak flow readings are usually a percentage of how your lungs work at their best. This is called your personal best peak flow.
• Spirometer. A spirometer measures how much air your lungs can hold and how quickly you can breathe out. This measurement is called forced expiratory volume (FEV-1). Your FEV-1 measurement is compared with the typical FEV-1 for people who don't have asthma. As with your peak flow reading, this comparison is often given as a percentage.

Your health care team will likely use this test during your office visits, but you may need to use a hand-held spirometer at home.