Pulmonary Function Tests (PFTs)

Pulmonary function tests consist of a wide range of tests designed to measure the capacity of your lungs to breathe in and exhale air. As a tool to determine the ability of a worker to wear respirators while performing parts of their job, PFT’s are sometimes required. They measure how efficiently your lungs can transfer oxygen to the bloodstream. To measure your lungs’ ability to exhale, our medical practitioners use a spirometer. The use of spirometers, or spirometry, works by measuring the volume of the lungs. The information gathered from spirometry is useful in diagnosing certain types of lung disorders, specifically obstructive lung diseases like asthma and chronic obstructive pulmonary disease (COPD).

Related Information:

Measuring lung volume helps detect restrictive lung diseases in which a person cannot inhale a normal volume of air. These diseases are caused by a number of factors, most commonly inflammation or scarring of the lung tissue (interstitial lung disease) or by abnormalities the individual’s chest cavity. Finally, diffusion capacity (DLCO) tests provide a fairly accurate estimate of how efficiently oxygen is being transferred from the air to the bloodstream by the lungs.

Conducting the Pulmonary Function Tests (PFTs)

A spirometry test is a relatively simple procedure. The spirometer is connected to an individual mouthpiece with a filter, which the person breathes into. The spirometer then records the rate and amount of air that is being inhaled and exhaled over a specific amount of time. These measurements are recorded by medical professionals.


In order to prepare for a spirometry test, the patient should avoid eating a heavy meal prior to the test and should  avoid smoking for at least 4-6 hours beforehand. If the patient is taking medications, or medication dispersion devices like an inhaler, specific instructions for conducting the test will be provided by the doctor.

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