Spirometry has been prescribed: how do you prepare for the breathing test?

Spirometry measures air volumes and flow rates. A doctor may prescribe it to investigate or monitor a condition such as asthma or COPD. It describes lung function; the result needs interpretation in your own situation.

Tell the team as soon as possible before the appointment about an acute respiratory or ENT infection, a transmissible infection or a recent procedure. Some situations affect whether the test can be performed: let the professional decide whether it should be postponed.

Ask for preparation instructions and report your breathing medicines. Only the doctor decides whether any should be withheld before the test. Instructions also cover meals, alcohol, smoking and exercise; wear clothes that do not restrict your chest.

During the test, you are usually seated with a nose clip and a mouthpiece. Staff guide you to breathe in, then blow out hard and for long enough. Understanding and following the instruction helps produce a measurement that can be interpreted.

Several attempts, usually at least three, are needed. Depending on the prescription, testing may be repeated after a bronchodilator. Report any dizziness or feeling unwell during the test so the team can adapt the procedure.

Results are explained and sent to the prescribing doctor; other tests may complete the assessment. Ask when and with whom to review them. A single number is not a basis for starting, stopping or changing breathing treatment on your own.