Pulmonary Function Tests

A Pulmonary Function Test (PFT) is done to determine if a person has a lung disorder or disease. The PFT requires breathing into a mouthpiece attached to a machine. This machine measures the amount of air a person breathes in and out, as well as the speed of the process.

A Respiratory Care Practitioner (RCP), who is specially trained in Pulmonary Function Testing, will perform the PFT. Your doctor will discuss the reason(s) for your PFT with you.

A PFT may be done to determine:

  • Risks before surgery
  • Overactive airways
  • Occupational disabilities
  • Chronic lung disease
  • Progress of a disease
  • Courses of treatment
  • Effects of various medications

Pulmonary Function Tests (PFTs) include:

  • Spirometry
  • DLCO
  • Lung volume testing
  • Arterial blood gas analysis
  • Oxygen saturation measurements
  • Maximum inspiratory and expiratory forces
  • Bronchoscopy
  • Methacholine challenge testing

During Your PFT

The test will take approximately 1 hour. Your RCP will be happy to answer any questions you have.

During the test, you will breathe into a tube attached to a machine. You will take a deep breath, then exhale as quickly and with as much effort as possible into the machine. You will do this a number of times, resting between breaths. The actual amount of time you will spend breathing into the machine will be about 15 minutes or less. You will feel no resistance as you breathe into the machine.

You will receive medicine to open your airways. A small amount of blood may be drawn from an artery in your arm to measure the level of oxygen in your blood. Drawing blood may be necessary because blood oxygen level is one measure of lung function.

Getting ready for your PFT or Methacholine Challenge Test

  • Do not take breathing medications (inhalers or nebulizers) before your test.
  • Do not take Singulair® for 24 hours before your test.
  • Do not eat a large meal for 4-6 hours before your test.
  • Do not smoke or use alcoholic beverages before your test.
  • Do not drink coffee, tea or other beverages that contain caffeine including soft drinks (Coke, Pepsi, Mountain Dew, etc.) before your test.
  • Do not eat any chocolate before your test.

Activities that should preferably be avoided prior to lung function testing:

  • Smoking within at least 1 hour of testing.
  • Consuming alcohol within 4 hours of testing.
  • Performing vigorous exercise within 30 minutes of testing.
  • Wearing clothing that substantially restricts full chest and abdominal expansion.
  • Eating a large meal within 2 hours of testing.