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Spirometry Lung Function Test

What is a Spirometry Test

Spirometry is a simple test used to help diagnose and monitor certain lung conditions by measuring how much air you can breathe out in one forced breath.

It's carried out using a device called a Spirometer, which is a small machine attached by a cable to a mouthpiece.

Who have Spirometry Tests?

Spirometry is used to diagnose

asthma,
chronic obstructive pulmonary disease (COPD), and
other conditions that affect breathing.

Spirometry may also be used periodically to monitor your lung condition and check whether a treatment for a chronic lung condition is helping you breathe better.

What can a Spirometry Test Diagnose?

A lung function test using Spirometry can help diagnose:

Asthma – a long-term condition in which the airways become periodically inflamed (swollen) and narrowed
Chronic Obstructive Pulmonary Disease (COPD) – a group of lung conditions where the airways become narrowed
Cystic Fibrosis – a genetic condition in which the lungs and digestive system become clogged with thick, sticky mucus
Pulmonary Fibrosis – scarring of the lungs

If you have already been diagnosed with one of these conditions, spirometry may be carried out to check the severity of the condition or see how you're responding to treatment.

What can a Spirometry Test Measure?

A spirometer measures the amount of air you can breathe out in one second and the total volume of air you can exhale in one forced breath.

These measurements will be compared with a normal result for someone of your age, height and sex. This comparison can indicate if your lungs aren't working properly.

The measurements will also show whether any area of your lungs is "obstructed", "restricted", or a combination of the two.

Types of Lung Disorders that Spirometry Can Detect

Lung disease can take many forms but generally, Spirometry can help detect either

Obstructive Airways Disease – where your ability to breathe out quickly is affected by a narrowing of the airways, but the amount of air you can hold in your lungs is normal (such as in asthma or COPD)
Restrictive Lung Disease – where the amount of air you can breathe in is reduced because your lungs are unable to fully expand (such as in pulmonary fibrosis).

Preparation for a Spirometry Test

While you'll be told about anything you need to do to prepare for the test. Common preparation for a Spirometry Test includes:

You may need to pause before the test any bronchodilator medication (medicines, usually inhaled, that help relax and widen your airways) but only as directed by your doctor

Things to avoid before a Spirometry Test include:

Smoking for 24 hours before the test,
Drinking alcohol,
Strenuous exercise
Eating large meals a few hours your test.

It's best to wear loose, comfortable clothing on the day of the test.

Possibly ask yourself if you have any concerns or specific worries relating to your breathing difficulties, as providing a more complete picture can help in creating a better solution if required.

Patient Instruction Sheet

During a Spirometry Test

A spirometry test requires you to breathe into a tube attached to a machine called a spirometer. Before you do the test, a nurse, a technician or your doctor will give you specific instructions. Ask questions if something is not clear.

Doing the test correctly is necessary for accurate and meaningful results.

During a spirometry test you will:

be seated with a clip placed on your nose to close your nostrils,
be asked to take a deep breath and breathe out as hard as you can for several seconds into the tube.

It's important that your lips create a seal around the tube so that no air leaks out.

The test is run at least three times to ensure consistent results. If the test results vary too much, you will be asked to repeat the test.

The highest value among three close test results is used as the final result.

The entire process usually takes less than 15 minutes.

Your doctor may give you an inhaled medication to open your lungs (bronchodilator) after the initial round of tests.

You'll need to wait 15 minutes and then do another set of measurements.

Your doctor then can compare the results of the two measurements to see whether the bronchodilator improved your airflow.

Results

The person carrying out the test won't usually be able to give you your results immediately.

The results will need to be looked at by a specialist first and will then be sent to the doctor who referred you for the test, who will discuss them with you a few days later.