Pulmonary function test

In medicine, pulmonary function tests, also called respiratory function tests, are "measurement of the various processes involved in the act of respiration: inspiration, expiration, oxygen and carbon dioxide exchange, lung volume and compliance, etc.

Respiratory flow volume loop of a patient without abnormalities.

Respiratory flow volume loop of a patient with obstructive lung disease.

Respiratory flow volume loop of a patient with restrictive lung disease.

Pulmonary function tests include:

• Blood gas analysis
• Capnography
• Exercise tests
• Lung volume measurements
• Peak expiratory flow rate
• Spirometry
• Ventilation-perfusion ratio (V/Q scan)

While precise measurements of these parameters take specialized equipment, often requiring considerable operator skill, it is worth noting that inexpensive peak flow meters are a vital part of patient self-management of asthma and several other respiratory diseases.