Service

Pulmonary Function Tests

Pulmonary function tests (PFTs) are a group of simple, painless breathing tests that measure how well your lungs take in air, how much they hold and how efficiently they move oxygen into the blood. They turn a vague symptom like “breathlessness” into clear, objective numbers.

What we measure

Spirometry — how much and how fast you can breathe out (FEV1, FVC and their ratio)
Lung volumes — the total amount of air your lungs can hold
Diffusion capacity (DLCO) — how well oxygen passes into the bloodstream
Reversibility — how your breathing responds to a bronchodilator

When they are useful

Diagnosing and monitoring asthma, COPD and interstitial lung disease
Investigating breathlessness or a long-standing cough
Assessing fitness of the lungs before surgery
Monitoring people with occupational or environmental exposure
Tracking how well treatment is working over time

What to expect

You sit and breathe into a mouthpiece, following the technician’s instructions for a series of breaths. The test is painless and usually takes 15–45 minutes; some parts are repeated after an inhaler to check the response.

Getting ready

Avoid a heavy meal and smoking shortly before the test
Skip certain inhalers beforehand only if we specifically advise it
Wear loose, comfortable clothing that does not restrict your chest