Some of the more common lung function tests include:-

Lung Function tests:

Spirometry - Spirometry is used to measure how much and how quickly you can blow air out of your lungs. For this test, you breathe into a mouthpiece attached to a recording device (spirometer). The information collected by the spirometer is printed out on a chart called a spirogram.

Spirometry Recording

Gas Diffusion - A gas diffusion test measures the rate at which a gas crosses the lungs' air sacs (alveoli) into your blood.  During the test you will breathe in air containing a very small amount of test gas from the equipment while measurements are taken.

Lung Volume Measurement - You will sit in a sealed, transparent box that resembles a telephone box (a “body plethysmograph”)) and will be asked to breathe in and out through a mouthpiece. Changes in pressure inside the box allow the calculation of the size of your lung.

A Body Plethysmograph in use

Skin Prick Tests - Skin prick tests are used to identify if you have any allergies. Small drops of fluid containing tiny amounts of allergens are dropped onto the forearm and the skin pricked with a small needle. Routinely 11 allergens are used including pollens, house dust mites and animal fur.  A positive reaction occurs if a small area of swelling, redness and often itching develops. You should stop using any antihistamine medicines for two days prior to these tests.

Methacholine Challenge - Methacholine provokes narrowing of the airways (bronchoconstriction) and can help in the diagnosis of asthma. Spirometry is performed before and after breathing increasing concentrations of methacholine. People with asthma tend to react to even a low level of methacholine. 

Exercise Tests - In most cases, enough information can be obtained from lung function tests done while sitting at rest. It is occasionally important to measure lung and heart function during exercise because some problems only show up then.  Depending on the type of exercise test a static bicycle or a treadmill is used.

• Cardiopulmonary exercise tests involve pedalling on a bicycle while measurements are taken including: the amount of oxygen used; carbon dioxide produced by the body; the total amount of air breathed in and out; together with the heart and breathing rate. Breathing is measured through a mouthpiece. Most people are able to pedal for about 5 to 10minutes. 
• The 6-minute walk test is a very simple procedure measuring how far you can walk in 6 minute periods along a corridor.
• Exercise tests are also performed with children who may have asthma. Spirometry is performed before and after exercise on a treadmill. Heart rate and oxygen levels are monitored whilst exercising.

When you have an exercise test, be sure to bring comfortable clothing and shoes  suitable for exercising and avoid having a heavy meal for 2-3 hours beforehand.

Sleep Studies:

Diagnostic Study - This test records several measurements during sleep including: blood oxyen levels; the flow of air through your mouth and nose; chest and abdomen movements; heart rate and rhythm; snoring; and sometimes brain activity and eye movement. The test is performed overnight and can be done in the hospital or at home.

CPAP trial - CPAP (Continuous Positive Airway Pressure) is the treatment used for most patients with sleep apnoea. The trial involves wearing a mask overnight which blows air into the airways to assist breathing and improve sleep.

CPAP Equipment