Understanding the Masterscope spirometer

A spirometer is connected to a mouthpiece. As you breathe into it, the device records the volume of air moved and the speed of exhalation. The result is a set of measurements that a trained clinician interprets alongside your symptoms, examination and medical history; the device alone does not provide a diagnosis.

Testing commonly involves a normal breath followed by a deep breath and a forceful, prolonged blow. Several attempts may be needed so the team can check that the readings are consistent. In some assessments, readings are compared before and after an inhaled medicine.

Follow the clinic's instructions about inhalers, smoking, meals and strenuous activity, because these can affect the reading. Wear comfortable clothing that does not restrict your chest. Tell the clinician if you feel unwell, have chest pain, recently had surgery, or become dizzy during breathing tests.

During the test, seal your lips around the mouthpiece and follow the technician's coaching. A cough, a leak around the mouthpiece or stopping early can make a result less reliable. Ask the clinic whether you should bring your inhalers and previous lung-function reports. Learn more about the [Spirometer](/technology/spirometer/) and [Spirometry](/treatments/diagnostics-and-screening/spirometry/).

Contact a clinician if breathlessness, wheezing or reduced exercise tolerance is new, persistent or worsening, even if a previous test was reassuring. Seek urgent help for severe difficulty breathing, blue or grey lips, fainting, confusion or chest pain. Stop the test and tell the technician immediately if you develop marked dizziness, chest discomfort or severe breathlessness.

Ask: What does each measurement show? Was the test quality adequate? Should any inhaler be withheld beforehand? Do I need repeat testing or another assessment? How do these results fit with my symptoms and treatment plan?