Pulmonary function tests (PFTs) are a group of breathing tests, each measuring different aspects of lung function, which are routinely used to assess lung health in people with bronchiectasis. If you are newly diagnosed, PFTs can help establish a baseline that shows how much the disease has affected your breathing. Over time, these tests track disease progression and evaluate how well treatments are working. Typically, patients undergo PFTs annually.

Common PFTs include:
• Spirometry — Measures airflow and how quickly air can be exhaled.
• Plethysmography — Measures how much air the lungs can hold.
• Diffusion capacity — Measures how well oxygen passes into the blood.
• Arterial or venous blood gas measurements — Measures the amount of oxygen and carbon dioxide levels in the blood.
• Oximetry — Measures the oxygen level in the blood.
• Six-minute walk test — Measures how your lungs and heart handle activity.