What is a PFT?

PFT stands for Pulmonary Function Test. It is group of tests that measures the function of the lungs, diagnoses problems with the lungs, and/or determines how well treatment for a lung condition is working.

What are some reasons for the procedure?

  • To help diagnose suspected lung conditions or diseases such as asthma, emphysema, or chronic bronchitis.
  • To quantify pulmonary disability.
  • To determine the effectiveness of medication given for a known lung condition.
  • To evaluate a patient’s condition before surgery.

Who should not have this test?

  • An unstable heart or lung disease.
  • Recently suffered a heart attack.
  • Active tuberculosis.
  • An acute asthma attack.
  • Respiratory distress.
  • Active bleeding from the lower respiratory tract.

What should I expect during the procedure?

During the procedure you will be asked to exhale and inhale in different patterns and speeds into pulmonary testing devices, and you will be able to rest between tests.

Immediately before each pulmonary function test, the doctor or technician will explain how each part of the test is performed and what device will be used. You will be sitting in an atmosphere-controlled booth. If you have trouble breathing, pain, or dizziness during testing, tell the doctor or technician immediately.

The most common tests are:

  • Peak Expiratory Flow – Take as deep a breath as possible, then exhale as forcefully as possible into the mouthpiece of a peak flow meter.
  • Forced Expiratory Time – Take as deep a breath as possible, then with your mouth wide open, blow out as hard as possible until your lungs feel completely empty, while your exhalation time is measured.
  • Maximum Ventilatory Volume – Blow as hard and as fast as possible into the mouthpiece of a spirometer with rapid in and out breaths for a period of 15 seconds.
  • Forced Vital Capacity – Take as deep a breath as possible, then blow out into the mouthpiece of a spirometer as hard and as fast and long as possible.
  • Oxygen Saturation Test – A small probe is painlessly strapped or clipped to one of your fingers or toes to measure the amount of oxygen being carried in the blood.
  • Allergen Challenge Tests – You are exposed to specific allergens during pulmonary function testing. This is only done in limited situations, under close and careful supervision.
  • Methacholine Provocation Test – People with asthma will experience a mild constriction of the airways when the drug methacholine is inhaled. This test may be done in situations where asthma is suspected but other pulmonary function tests have not shown a clear diagnosis of asthma.

After the test you will be able to rest until you feel able to leave. If you experience headaches, nausea, muscle aches, dizziness, or general ill feelings, shortness of breath, difficulty breathing, or chest pain after your test, call your doctor immediately.