The PFT medical abbreviation stands for pulmonary function test, a group of breathing tests that measure how much air the lungs hold, how fast air moves out, and how well oxygen passes into the blood. The plural, PFTs, is just as common, since several tests are usually done in one visit.
PFTs help diagnose and follow conditions such as asthma, COPD and scarring lung diseases, and they are often checked before major surgery. The reports are dense with letters like FEV1 and DLCO. This page explains the main parts in plain language and shows how a typical line reads.
At a glance
Stands for
Pulmonary function testPlural or forms
PFT, PFTs, lung function testsMain parts
Spirometry, lung volumes, diffusing capacity (DLCO)Used in
Pulmonology, allergy, primary care, preoperative testingDone by
Respiratory therapists or pulmonary lab technologistsDo not confuse with
LFT (liver function tests) and peak flow
The tests inside a PFT visit
| Test | What you do | What it shows |
|---|---|---|
| Spirometry | Take a full breath, then blow out as hard and long as you can | How fast and how much air you can push out |
| Bronchodilator response | Repeat spirometry after an inhaled airway opening medicine | Whether narrowed airways open up, as in asthma |
| Lung volumes | Breathe in a sealed booth or through a tube with a tracer gas | Total size of the lungs and air left after breathing out |
| DLCO | Breathe in a small safe gas sample and hold it briefly | How well gas moves from the lungs into the blood |
Not every visit includes every test. The order from the clinician names which ones are needed.
Making sense of FEV1, FVC and the ratio
Spirometry gives the numbers people ask about most. FVC, forced vital capacity, is the total air you can blow out after a full breath. FEV1, forced expiratory volume in one second, is how much of that comes out in the first second. Results are shown as a percent of the value predicted for someone of your age, height and sex.
The ratio of FEV1 to FVC is the key to the pattern. When it is low, commonly below about 0.70 in adults, air is having trouble getting out, which is called an obstructive pattern and is seen in asthma and COPD. When the ratio is normal but the lungs are small, the pattern is called restrictive, which can come from lung scarring, chest wall problems or weak breathing muscles. Lung volume testing confirms restriction.
Reading a PFT medical abbreviation line in a note
A pulmonology clinic note: "PFTs: FEV1/FVC 0.62, FEV1 58% predicted, no significant BD response, DLCO 71%." The low ratio shows obstruction. FEV1 at 58 percent of predicted puts it in a moderate range, the airways did not open much with the inhaler, and gas transfer is mildly reduced. A pattern like this is often seen in COPD.
BD stands for bronchodilator. Some reports also list TLC for total lung capacity and RV for residual volume, the air left behind after a full breath out.
Why doctors order PFTs
The tests answer practical questions: Is shortness of breath coming from the lungs? Is it asthma, COPD or something else? Is a known lung disease stable, better or worse? Is someone fit for lung or heart surgery? Clinicians also use them to check for lung effects of some medicines and of work exposures. Paired with imaging such as a CXR or CT and, in sicker patients, an ABG, they give a fuller picture.
In scarring diseases such as ILD, a falling DLCO or FVC over time can be an early sign of change.
Getting ready for the test
Clinics usually ask you to avoid smoking, heavy meals and hard exercise for a few hours beforehand, and to wear loose clothing. Some people are asked to hold certain inhalers before the visit so the bronchodilator test is accurate, but only do this if the lab or your prescriber tells you to. The tests take effort, and some people feel light headed or tired briefly. Coaching from the technologist helps get the best result.
Frequently asked questions
What does the PFTs medical abbreviation mean in a chart?
PFTs means pulmonary function tests, the breathing tests that measure lung size, airflow and gas transfer. The plural is used because several tests are usually done together.
Is spirometry the same as a PFT?
Spirometry is one part of a full PFT. A complete set often adds lung volumes and diffusing capacity, but sometimes spirometry alone is ordered.
How long does a pulmonary function test take?
Spirometry alone can take around 15 to 30 minutes. A full set with lung volumes and DLCO may take an hour or so, depending on the lab.
What is a normal FEV1/FVC ratio?
In adults, a ratio of about 0.70 or higher is commonly treated as normal, though many labs use an age based lower limit instead. A lower ratio suggests the airways are narrowed.