Lung volume spirometer: understanding the test

A lung volume spirometer records air moved during a forced breath, helping clinicians assess airflow and some measures of breathing capacity. It does not simply provide a pass-or-fail result. A clinician compares the pattern with your symptoms, history, examination and other findings.

You breathe through a disposable mouthpiece while the device tracks the air you move. A full inhalation followed by a strong, sustained exhalation lets the team assess the amount and speed of air leaving your lungs. Repeating the manoeuvre helps confirm the quality of the effort. Spirometry is the test; the spirometer is the instrument that captures its measurements.

Follow the appointment instructions about food, smoking, activity and inhaler timing. Wear loose clothing and tell the tester about current chest infection, recent surgery, pregnancy or medicines. Sit or stand as instructed, keep a firm seal around the mouthpiece and follow coaching closely. It is normal to need rest between attempts. Do not change prescribed treatment unless the clinician who manages it tells you to.

Stop and tell the tester if you develop chest pain, marked dizziness or severe breathlessness. Outside the appointment, emergency assessment is needed for breathlessness at rest, blue lips, fainting, confusion, or difficulty speaking because of lack of air. Worsening wheeze or cough should be discussed promptly, especially if your usual reliever is not helping.

Ask which lung-volume measures are being assessed, whether your inhalers should be taken as usual, how reliable the effort was, when you will receive an explanation and what follow-up would match your symptoms.