What do lung function tests involve?

 

1. Spirometry

Spirometry measures the amount of air in the lungs and how fast it moves through the airways when you exhale. By measuring how much air you exhale, and how quickly, spirometry can evaluate a broad range of lung diseases. This test involves breathing into a mouthpiece connected to a machine called a spirometer. You will be given a soft nose clip to wear during the procedure so that all of the air you breathe travels through your mouth, rather than your nose. You will be asked to take as big a breath in as you can and then exhale all the air out as quickly and completely as possible. In some cases, you may be asked to repeat the test after taking a medication that relaxes the airway muscles (such as Ventolin) to determine the effect of that medication on your results.

 

2. Transfer factor

To measure transfer factor, you breathe a harmless gas for a very short time. The amount of the gas in the air you breathe out is then measured. The difference in the amount of gas inhaled and exhaled measures how effectively gas travels from the lungs into the blood. This test allows the doctor to estimate how well the lungs move oxygen from the air into the bloodstream

 

3. Plethysmographic lung volumes

For this test, you sit inside a small airtight box similar to a phone booth and breathe into a mouthpiece while pressure and air flow measurements are collected. The changes in pressure inside the box are used to calculate the amount of air inside the lung as you breathe. From inside the box you will be able to see and hear the instructions of the staff member carrying out the test.

 

4. Bronchial provocation tests

Bronchial provocation tests are done to measure the response of your airways to substances that may be causing asthma or wheezing. This test involves spirometry as described above. You will be asked to repeat the spirometry test several times after inhaling the challenge agent, usually in slowly increasing amounts. By doing this, the doctor can establish how sensitive your airways are to agents that can provoke wheezing.

 

5. Maximal Respiratory pressures

These tests measure the strength of the muscles used to breathe. You will be asked to breathe in and then out into the mouth piece as strongly as you can.

 

 

 

Products to be avoided prior to testing