What is a bell spirometer?

A bell spirometer uses a movable bell or chamber that rises and falls as air moves through the equipment. The movement is converted into a measurement of breathing volume. It is different from a home peak-flow meter, which focuses on how quickly air can be blown out. Results are interpreted with your symptoms, examination, age, height, and testing technique. A single reading is not a diagnosis by itself.

During spirometry, you usually sit upright, place your lips around a mouthpiece, and follow instructions to breathe in fully before blowing out with sustained effort. The technician may repeat the manoeuvre to check consistency and may sometimes compare readings before and after an inhaled medicine. Wear comfortable clothing and follow the testing centre's instructions about medicines or meals. Tell the technician if you feel dizzy, unwell, or unable to continue.

Tell the testing team before the test if you have chest pain, a recent operation, an active respiratory infection, or severe breathlessness. Stop and seek immediate help for intense chest pain, marked breathing difficulty, fainting, or blue lips. Mild temporary breathlessness or light-headedness can occur with forceful breathing, but it should settle after rest; report it promptly if it does not.

Why has this test been requested? Which breathing measurements will be reviewed? Should I change any inhalers before testing? What will happen if the result is difficult to interpret?