Lung Function Testing

Proper preparation ensures accurate test results and avoids factors that might interfere with measurements.

Medications:

• Inhalers

Continue taking your medications unless your doctor has specifically advised you to stop before the test. Please bring all your inhalers with you on the day, including your reliever inhaler, as you may need to use them during the testing.

• Antihistamines

Avoid taking any antihistamines for 48 hours before the test, as these can affect certain measurements, especially for the skin prick test.

• Other Medications

If you’re on additional medications that might impact breathing, consult your healthcare provider, who will advise you accordingly.

Smoking and Caffeine:

Try not to smoke for at least 24 hours before the test.

Avoid caffeine on the day of your test (e.g., coffee, tea, or cola drinks), as it can influence your breathing.

Eating and Exercise:

Refrain from eating a large meal within two hours before the test, as a full stomach can make deep breathing challenging.

Avoid vigorous exercise on the day of the test, as it may temporarily impact your lung function.

Clothing:

Wear loose, comfortable clothing to allow free movement of your chest. This will help you breathe deeply during the tests.

Arrival:

Arriving a little early will give you time to relax and settle in before starting. Calm, steady breathing is important for accurate results.

Following preparation guidelines and understanding each test will help you feel more comfortable and confident, ultimately providing your healthcare team with the precise information needed to manage and improve your respiratory health.

Lung function tests can be performed in several ways, but the general steps are quite similar. Here’s what you can expect for the most common lung function tests:

Spirometry Test

• You’ll sit on a chair with a soft clip on your nose to ensure you breathe only through your mouth.
• You’ll seal your lips tightly around a mouthpiece connected to a device called a spirometer.
• You’ll take a deep breath in and exhale forcefully into the mouthpiece. The spirometer will measure the volume and speed of your exhaled air.
• In some cases, you’ll inhale a medicine designed to open your airways and then repeat the test to see if the medication improves your airflow.

Body Plethysmography (Lung Volume Test)

• You’ll sit inside a small, clear, airtight booth resembling a telephone booth.
• A soft clip will be placed on your nose to ensure you breathe only through your mouth.
• You’ll seal your lips around a mouthpiece and follow instructions to breathe in and out.
• Changes in air pressure within the booth will measure how much air your lungs can hold and how much air remains after you exhale.
• Alternatively, the test may involve breathing a special gas mixture for a few minutes while wearing a nose clip, without the need for the airtight booth.

Gas Diffusion Test

• You’ll sit on a chair with a soft nose clip to ensure you breathe only through your mouth.
• You’ll seal your lips tightly around a mouthpiece connected to a spirometer.
• You’ll inhale a small, safe amount of carbon monoxide and hold your breath for about 10 seconds.
• Afterward, you’ll exhale into the mouthpiece. The spirometer will measure the carbon dioxide levels in your breath, which helps determine how effectively your lungs absorb gases into your bloodstream.

Lung function tests are generally low-risk. However, some individuals may experience light-headedness, dizziness, or fatigue from deep breathing. Coughing is also a common reaction. For lung volume tests, some may feel uneasy in enclosed spaces. If you have any concerns, please discuss them with your consultant prior to your appointment.