FEV1 Lung Function Test

Last updated: 12 December 2017

What is the FEV1 lung function test?

The FEV1 (or forced expiratory volume-one second) measures the volume of air, in litres, exhaled during the first second of a forceful exhalation. It is part of the battery of respiartory function tests.

A low FEV1 is associated with obstructive lung diseases such as asthma and chronic obstructive pulmonary disease.

When would you need a FEV1 test?

A FEV1 test may be requested by your doctor for symptoms such as shortness of breath (dyspnoea), cough or wheezing.

How is the FEV1 test performed?

FEV1 tests involve breathing into a mouthpiece, which is connected to a small machine via some tubing.

You will be required to breathe in and out as deeply as possible, and then as fast and as forcefully as possible.

The FEV1 test may make you feel temporarily short of breath, but is otherwise harmless.

More sophisticated testing such as gas transfer tests require the patient to breathe into a closed system, via a tight-fitting face mask.

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FEV1 test results explained

FEV1 tests usually aim to distinguish between obstructive lung diseases such as asthma, emphysema and chronic bronchitis, versus restrictive lung diseases such as pulmonary fibrosis.

The FEV1/FVC (forced vital capacity) ratio is decreased in obstructive lung disease, and usually increased in restrictive patterns of lung disease.

Related specialists

Related procedures

  • Bronchoscopy

Related tests

Also known as

  • FEV (Forced Expiartory Volume)



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This article is for informational purposes only and should not be taken as medical advice. If in doubt, HealthEngine recommends consulting with a registered health practitioner.