Pulmonary Function Tests (PFTs) are a group of non-invasive diagnostic tests that assess lung function by measuring how well the lungs can inhale, exhale, and exchange gases. PFTs are essential for diagnosing, monitoring, and managing respiratory conditions such as asthma, chronic obstructive pulmonary disease (COPD), interstitial lung disease, pulmonary fibrosis, and restrictive or obstructive lung disorders. They also evaluate the effects of environmental or occupational exposures on lung health.

The primary components of PFTs include measurements of lung volumes, capacities, airflow rates, and gas exchange efficiency. Spirometry, the most common PFT, measures the amount and speed of air a person can inhale and exhale, helping identify obstructive or restrictive patterns. Other specialised tests include lung volume measurement, diffusion capacity (DLCO), and bronchial challenge tests. These tests provide quantitative data on lung function, airflow limitation, and gas transfer efficiency. PFTs are performed using a spirometer or advanced pulmonary testing systems. The patient is instructed to breathe in and out through a mouthpiece while wearing a nose clip to ensure accurate measurements. The procedure is safe, non-invasive, and generally well-tolerated, taking about 30–60 minutes depending on the tests performed. Proper patient cooperation and technique are crucial for reliable results.

The results are interpreted by pulmonologists or respiratory therapists in the context of patient history, symptoms, and other investigations. PFTs are invaluable in assessing disease severity, monitoring progression, evaluating treatment response, and determining fitness for surgery or occupational requirements. They also help guide inhalation therapy, rehabilitation, and lifestyle modifications. By providing a precise, objective assessment of lung function, Pulmonary Function Tests contribute significantly to early diagnosis, individualised treatment planning, and improved respiratory health, enhancing quality of life for patients with chronic or acute lung conditions.