Pulmonary Function Test (PFT)

Overview

A pulmonary function test is a non-invasive procedure that measures lung volumes, airflow, and gas exchange. PFTs are an important tool for your pulmonologist to help diagnose or see the progression of various pulmonary diseases and therefore choose a treatment option that best fits your condition.

PFT has three different components: (Pulmonary Function Tests, n.d.)

Spirometry: This is the most commonly used test. It measures FVC (forced Vital Capacity) and FEV1 (Forced Expiratory Volume in the 1st second of exhalation).
LVM: Lung Volume Measurements. This test measures the total lung capacity and is important in differentiating between obstructive and restrictive lung diseases mentioned below (Peleg, 2018).
DLCO: This test measures the ease of transfer of CO (carbon monoxide) molecules between the alveoli and hemoglobin molecules. This is important because it can show how well the lungs can diffuse and exchange gasses in our lungs.

There are two main categories of pulmonary diseases

Obstructive diseases: are associated with airway obstruction that prevents patients from being able to exhale all the way out, such as:

COPD (chronic obstructive pulmonary disease)
Asthma
Cystic fibrosis
Bronchiectasis

Restrictive diseases: are associated with lung restriction, which prevents patients from being able to expand their airway and thus reduces their ability to inhale, such as:

Asbestosis
Sarcoidosis
Pulmonary fibrosis

How to prepare for your PFT test. (Pulmonary Function Tests, n.d.)

Make sure to:

Stop taking certain medicines before the procedure, if instructed by your healthcare provider, such as inhalers.
Stop smoking before the test if instructed by your healthcare provider. Ask your provider how many hours before the test you should stop smoking.
Not to eat a heavy meal before the test, if instructed by your healthcare provider.
Follow any other instructions your healthcare provider gives you.

If you have any questions about pulmonary function testing, please don’t hesitate to contact Advanced Respiratory and Sleep Medicine today.

References

Peleg, C. (2018, May 13). Spirometry Isn't Enough to Diagnose Lung Diseases. Pulm One. Retrieved April 3, 2022, from https://www.pulm-one.com/why-more-than-spirometry-should-be-measured/

Pulmonary Function Tests. (n.d.). Johns Hopkins Medicine. Retrieved April 3, 2022, from https://www.hopkinsmedicine.org/health/treatment-tests-and-therapies/pulmonary-function-tests