Why is a spirometer used in spirometry?

Spirometry records how much air you can move and how quickly you can breathe it out after taking a full breath in. The pattern can help a clinician assess symptoms such as wheeze, cough, breathlessness, or reduced exercise tolerance, and it can support monitoring of known lung conditions. The test result is compared with information about your age, height, sex, symptoms, and medical history. Results are not interpreted in isolation: effort, technique, a recent illness, and the ability to produce repeatable blows all affect the recording.

Follow the appointment instructions about inhalers, smoking, exercise, food, and recent respiratory infections; do not stop prescribed treatment unless you have been specifically told to do so. During the test, a nose clip may be used and you will be coached to seal your lips around a mouthpiece, breathe in fully, then blow out hard and keep going until asked to stop. Several attempts may be needed to obtain a dependable tracing. Tell the clinician if you feel dizzy, develop chest discomfort, or cannot continue.

Do not wait for a routine lung function test if you have severe breathlessness, chest pain, blue or grey lips or face, confusion, fainting, or difficulty speaking because you are short of breath. Seek urgent medical help for these symptoms. Contact the testing service before attending if you have a new fever, a contagious respiratory illness, or a recent procedure that may affect whether forceful breathing is appropriate.

Ask whether the blows were technically reliable, what the pattern may suggest, and whether you need repeat testing or another assessment. If you use inhalers, ask whether the plan changes and how future spirometry should be prepared for.