Pulmonary Function Testing Overview

Why the Test is Performed

Pulmonary function tests are done to:

• Diagnose certain types of lung disease (especially asthma , bronchitis , and emphysema )
• Find the cause of shortness of breath
• Measure whether exposure to contaminants at work affects lung function

It also can be done to:

• Assess the effect of medication
• Measure progress in disease treatment

Spirometry measures airflow. By measuring how much air you exhale, and how quickly, spirometry can evaluate a broad range of lung diseases.

Lung volume measures the amount of air in the lungs without forcibly blowing out. Some lung diseases (such as emphysema and chronic bronchitis) can make the lungs contain too much air. Other lung diseases (such as fibrosis of the lungs and asbestosis ) make the lungs scarred and smaller so that they contain too little air.