Spirometry: the most common lung function test

Spirometry is the most common lung function test. It is used to determine how well your lungs work by measuring how much air you can breathe in and out, and how quickly and easily you exhale. In order to perform the test, you will need to use a spirometer, a specific device designed to measure the air flow and amount in your lungs.

Spirometry is very useful for both the diagnosis and monitoring of chronic lung conditions.

1. What is a lung function test?

Lung function tests, also known as pulmonary function tests, are breathing tests used to determine the functionality of your lungs.

There are several different kinds of lung function tests: some are intended to measure your lung capacity, others are used to test how physical exercise affects your breathing, others are designed to check how well oxygen from your lungs is absorbed into the blood. They are usually non-invasive and some of them can be even performed at home, provided the patient is supplied with the necessary equipment.

The most common pulmonary function tests are:

• Lung volumes or plethysmography. It measures the amount of air in your lungs at different points during inhalation and exhalation.
• Gas diffusion study. It is used to test how effectively oxygen and other gases get transferred from your lungs to the blood.
• CPET, cardiopulmonary exercise test. It is performed to test your cardiopulmonary function, as well as you muscular ability, during physical exercise.
• Spirometry. It is by far the most common lung function test, measuring how much air you can breathe in and out, as well as how fast and easily you can exhale.

1. When is spirometry recommended?

Your physician may suggest a spirometry test when they suspect you may suffer from a chronic condition such as asthma, COPD, chronic bronchitis, emphysema or pulmonary fibrosis. Symptoms to look out for include chest tightness, cough (especially when mucus or phlegm are produced), shortness of breath, wheezing or general breathing difficulties.

Spirometry is also recommended to periodically monitor the health and functionality of your lungs in case you have already been diagnosed with a chronic pulmonary disease, and it can help to assess whether the medical treatment is effective.

1. Which data can I get from spirometry?

Some of the most common parameters measured in spirometry are the following:

• FEV1, i.e. Forced expiratory volume in 1 second: this is how much air you can exhale in 1 second.
• FVC, i.e. Forced vital capacity: this is the amount of air you can exhale by blowing out fast after inhaling as deep as you can.
• FEV1/FVC ratio. A ratio below 70% indicates you may have an obstructive respiratory condition.
• VC, i.e. vital capacity: this is the amount of air you can exhale by blowing out at a steady rate.
• IVC, i.e. inspiratory vital capacity: this is the amount of air you can inhale after a full expiration.

1. Is spirometry safe?

Spirometry is generally considered safe, as it is non-invasive, quick and easy to perform.

Patients are usually seated during the test, and are often advised to wear loose clothing and avoid heavy meals for a few hours before it, in order to make deep breathing easier.

The only downside is you may feel lightheaded or dizzy after the test, due to the large amount of air you are required to breath, but it usually wears off in a few minutes.

1. Want to know more about spirometry?

With over 30 years of experience, MIR is a global medical device leader in Spirometry, Oximetry and MedTech solutions. Check out the News & Events section on our website for monthly updates on spirometry, as well as tips and suggestions on how to cope with chronic lung conditions in the most fulfilling and functional way.