What should you know about an old spirometer?

A spirometer records the amount of air you breathe out and how quickly you exhale. The result can help a clinician assess airflow limitation and compare readings with your symptoms and examination. An older machine may have a worn mouthpiece, blocked tubing, outdated software, or calibration drift. These issues can produce a result that does not reflect your usual breathing. A single reading is therefore interpreted in context rather than treated as a diagnosis by itself.

Tell the clinician about current breathing symptoms, smoking or vaping, chest discomfort, recent infection, and medicines used for breathing. Follow the instructions about meals, exertion, and inhalers that your service gives you; do not stop a prescribed medicine without advice. Use a clean, suitable mouthpiece and ask whether the spirometer has been checked and calibrated. During Spirometry, you will usually breathe through the mouthpiece and repeat forceful breaths so the clinician can judge consistency.

Seek urgent medical help for severe breathlessness at rest, blue or grey lips, fainting, confusion, or chest pain that is severe or persistent. Stop a breathing test and tell the clinician if you become very dizzy, develop chest pain, or cannot recover your breathing comfortably. An old machine should be replaced or checked when its readings are unreliable; it should not delay assessment of worsening symptoms.

Ask what the test is assessing, whether the device has current calibration checks, how your effort affects the result, and whether repeat testing or another assessment is appropriate.