Spirometers are used by a qualified medical professional to assist in the diagnosis of illnesses that may affect a patient’s lung function. This may be a nurse or doctor within a private clinic, a hospital, or a trained occupational health specialist within a company.

A spirometer may also be used periodically to assess the condition of a person’s lungs i.e., in the workplace where respiratory sensitisers are present and can influence lung function.

A spirometry test involves a small medical instrument called a spirometer, along with a mouthpiece. A patient will take a deep breath and breathe with force into the mouthpiece which is attached to the spirometer. The results of the spirometry test are then analysed and interpreted accordingly.

Relaxed (or slow) Vital Capacity (VC) - The volume of air that can be slowly expelled from the lungs from a point of maximal inspiration to maximum expiration.

Forced Vital Capacity (FVC) - The volume of air that can be forcibly expelled from the lungs from a point of maximal inspiration to maximum expiration.

Forced Expiratory Volume in 1 second (FEV1) - The volume of air that can be forcibly expelled from the lungs from a point of maximum inspiration in the first second of an FVC manoeuvre.

FEV1/FVC ratio or FEV1% - The FEV1/FVC ratio is the FEV1 expressed as a percentage of the FVC (or VC if this is greater).