Coping with...LUNG FUNCTION TESTS

These breathing tests will provide your doctor with a detailed assessment of how well your lungs are working

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Tests including spirometry, lung volume and diffusion/gas transfer assessments - measure your airway function, the size of your lungs and efficiency of gas exchange, such as oxygen movement in the lungs. They take about 45 minutes, and involve you being seated and breathing into specialist equipment, via a filter and a mouthpiece.

Spirometry measures the amount of air that you inhale and exhale, and how fast you can exhale. You'll need to breathe normally, then breathe in fully and out until your lungs are completely empty.

Then you'll have to blow out as hard and as fast as possible with a clip on your nose, to ensure you mouth-breathe with no air escaping from your nose.

You'll repeat the test several times for accurate results. Sometimes you will be asked to perform spirometry before and 10-20 minutes after using an inhaler - this reversibility test helps the doctor identify whether the inhaler improves your breathing. You may have been warned to withhold certain of your usual medications beforehand.

Lung volumes measure the total size of your lungs, and amount of air remaining in the lungs after a complete breath out, to give detailed information about how your lungs function.