What are pulmonary function tests? Pulmonary function tests (PFTs) measure how well your lungs take in and exhale air and how efficiently they transfer oxygen into the blood. There are several different tests. Spirometry measures how well the lungs exhale (breathe out). Lung volume measures how well the lungs inhale (breathe in). Testing the diffusion capacity of carbon monoxide (DLCO) shows how efficiently the lungs transfer oxygen from the air into the bloodstream.
Pulmonary function tests help:
- Diagnose diseases of the lung such as asthma, chronic bronchitis, and emphysema.
- Determine the cause of shortness of breath.
- Measure the effects of exposure to chemicals, coal dust and other toxins on your lung function.
- Measure the effectiveness of medicines and other treatments.
- Detect lung disease at an early stage before you have symptoms.