A complex pulmonary function test, also known as a lung function or respiratory function test, is a complete evaluation of the respiratory system that is used to check how well your lungs and airways function. A complex pulmonary function comprises of different smaller tests including spirometry, lung volumes and gas transfer.

The purpose of a complex pulmonary function test is to identify how well your lungs work and to determine if there is any pulmonary impairment. It is used to look for the cause of breathing problems such as shortness of breath, cough or wheeze.

You may be referred for a lung function test if:

• You already have a pre-existing lung condition
• Your doctor is checking your response to treatment or whether your lung function has improved or remains stable
• You are having symptoms of lung disease or if lung disease is suspected
• You are having surgery in the near future

To prepare for your test, please do not take any of your usual short-acting puffers for 4 hours prior to testing or any long-acting puffers for 8 hours prior. As well, it is important to not have any caffeine prior including coffee, tea, energy drinks or chocolate as this can open your airways which can potentially affect your results. You should also try to avoid smoking or strenuous exercise prior to the test.

Please inform the scientist if you have had any recent eye, chest or abdominal surgery as you will need to defer the test until you have recovered. You should not have complex pulmonary function testing after a recent heart attack.

FeNO stands for fractional concentration of exhaled nitric oxide. A FeNO, or exhaled nitric oxide test, is typically performed on patients with allergic or eosinophilic asthma. It is used to determine the amount of inflammation present in your lungs.

A six minute walk test measures how far you can walk on a flat surface in six minutes. It is organised by your doctor to find out how your heart and lungs respond to exercise. During the test, the nurse or scientist will record your time, distance, heart rate and oxygen levels.