What should you know about peak expiratory flow and spirometry test?

A peak-flow reading records the fastest speed of exhalation from a forceful breath. It is often useful for tracking change over time, especially when readings are taken in a consistent way. Spirometry records a fuller pattern of airflow, including the amount exhaled and how quickly it leaves the lungs.

Results are interpreted against your symptoms, examination and test technique. They may help assess asthma, COPD, bronchiectasis or a chronic cough, but one reading does not explain every breathing problem. A spirometer is the device used for spirometry, while peak flow uses a smaller handheld meter.

Wear comfortable clothing, follow the clinic’s instructions about inhalers, and avoid a heavy meal or strenuous activity immediately beforehand if you have been told to do so. Sit or stand as directed, seal your lips around the mouthpiece, and give a strong, fast effort. The clinician may repeat attempts to check consistency.

Keep a record of home peak-flow readings if requested, including symptoms and medicine use. Do not change inhaler therapy or other treatment from a single result without discussing the pattern with your clinician. Smoking cessation support can improve the wider plan for lung health.

Seek emergency help for severe breathlessness, difficulty speaking because of breathing, blue or grey lips, confusion, fainting, or rapidly worsening wheeze. If your readings fall below the personal range given by your clinician, follow your written action plan and seek advice according to its instructions.

Ask which test is most useful for your symptoms, whether you should pause any inhaler before testing, how to record peak-flow readings, and what range should trigger action. Discuss whether inhaler therapy, further assessment or repeat testing is appropriate.