What should you know about standardisation of spirometry?

A trained operator explains the breathing manoeuvre, checks that the mouthpiece is sealed, and encourages a full breath in followed by a rapid, forceful breath out. The test is repeated so the readings can be compared for consistency. The spirometer should be checked and maintained, and the result is recorded with relevant details such as symptoms, medicines, and the quality of the blows. Poor effort, coughing, a leak, or stopping too soon can make a reading less useful. Spirometry is one part of an assessment and may help clinicians investigate asthma, COPD, bronchiectasis, or a chronic cough; it does not by itself explain every breathing problem.

Follow the appointment instructions about eating, smoking, exercise, and inhalers. Wear clothing that does not restrict your chest or abdomen. Tell the operator if you feel unwell, have chest pain, have recently had surgery, or find forceful breathing difficult. During the test, sit upright, follow each instruction, and say if you feel dizzy or short of breath. Bring a list of medicines and ask whether any inhaler should be paused; do not stop prescribed treatment without advice. Results are easier to interpret when the operator records whether a bronchodilator was used and when.

Spirometry can briefly cause coughing, chest tightness, breathlessness, or light-headedness. Tell the operator immediately if symptoms are severe or do not settle after resting. Seek urgent medical help for severe breathing difficulty, blue or grey lips, fainting, new chest pain, or confusion. If breathing symptoms continue after the appointment, contact a clinician. A test result that is difficult to perform or interpret may need repeating or may be combined with other assessments, rather than treated as a diagnosis on its own.

Ask which part of the result is abnormal, whether the blows met quality standards, whether you should use your inhaler before a repeat test, and what the next step will be. You can also ask how smoking affects lung function and whether a smoking cessation programme or inhaler therapy is relevant to your care.