Pulmonary function tests measure how well your lungs are working.

Specialists use the tests to reach a diagnosis and determine the severity of lung disease, such as asthma, bronchitis and emphysema.

The tests also help assess how well treatment for lung disease is working.

More specifically, pulmonary function tests measure:

• How much air your lungs can hold (lung capacity or lung volume)
• How quickly you move air in and out of your lungs
• How well your lungs exchange oxygen for carbon dioxide

Types of Pulmonary Function Tests

Tests are noninvasive, quick, easy and painless. They may be conducted by a respiratory therapist.

Pulmonary function tests include:

• Arterial blood gas (ABG) – test to determine whether you are getting enough oxygen
• CT scan – provides a more enhanced image than X-ray
• Chest X-ray – imaging test to see how well your lungs and heart are working
• Electrocardiogram (EKG) – electrodes placed on your body provide data on the function of your heart
• Peak flow monitor – used on children to measure airflow out of their lungs
• Pulse oximetry – measures the oxygen level of your blood
• Sputum culture – helps determine the cause of excess sputum (phlegm) in your lungs
• Spirometry – measures the amount of air you exhale and how quickly you exhale