Pulmonary function spirometry: what to know

You breathe into a spirometer through a clean mouthpiece while a clinician guides your efforts. The device records the volume of air exhaled and the speed of that exhalation. Repeated blows help check whether the result is consistent. Sometimes the test is repeated after inhaled medicine to see whether airflow changes. The pattern can support assessment of asthma, COPD, bronchiectasis, or a persistent cough, but results need to be interpreted alongside symptoms and examination.

Wear comfortable clothing that does not restrict your chest. Follow the clinic's instructions about inhalers, smoking, meals, and strenuous activity because these can affect the reading. Tell the clinician about recent chest infection, dizziness, chest pain, or any condition that makes forceful blowing difficult. During the test, seal your lips around the mouthpiece, breathe as instructed, and stop if you feel unwell.

Spirometry is usually arranged to investigate an ongoing breathing concern, not to manage severe distress at home. Seek urgent help for severe breathlessness at rest, blue-grey lips, confusion, or inability to speak in full sentences. Contact the clinic if coughing, wheezing, dizziness, or chest discomfort continues after testing. Do not change inhaler treatment based on a single reading without discussing the result.

What question is this test intended to answer? Should I pause any inhaler beforehand? Could my result be affected by a recent infection or smoking? Will I need repeat testing, and how will the findings change my treatment?