Pulmonary Function Test


Pulmonary function tests (PFT’s) are a group of tests that measure how well your lungs work. This includes how well you’re able to breathe and how effective your lungs are able to bring oxygen to the rest of your body. Your doctor may order these tests: If you’re having symptoms of lung problems if you’re regularly exposed to certain substances in the environment or work place to monitor the course of chronic lung disease, such as Asthma or Chronic Obstructive Pulmonary Disease (COPD) to assess how well your lungs are working before you have surgery. PFTs are also known as lung function tests.

Why are these tests done?

Your doctor will order these tests to determine how your lungs are working. If you already have a condition that’s affecting your lungs, your doctor may order this test to see if the condition is progressing or how it’s responding to treatment. PFT’s can help diagnose: Asthma, Allergies, Chronic Bronchitis, Respiratory infections, Lung Fibrosis, Bronchiectasis, a condition in which the airways in the lungs stretch and widen. COPD, which used to be called Emphysema Asbestosis, a condition caused by exposure to Asbestos, Sarcoidosis, an inflammation of your lungs, Liver, Lymph nodes, eyes, skin, or other tissues Scleroderma, a disease that affects your connective tissue Pulmonary Tumor, Lung Cancer, weaknesses of the chest wall muscles.


How do I prepare for pulmonary function tests? If you’re on medications that open your airways, such as those used for Asthma or Chronicbronchitis, your doctor may ask you to stop taking them before the test. If it isn’t clear whether or not you should take your medication, make sure to ask your doctor. Pain medications may also affect the results of the test. You should tell your doctor about any over-the-counter and prescription pain medications you’re taking. It’s important that you don’t eat a large meal before testing. A full stomach can prevent your lungs from inhaling fully. You should also avoid food and drinks that contain caffeine, such as chocolate, coffee, and tea, before your test.

Caffeine can cause your airways to be more open which could affect the results of your test. You should also avoid smoking at least an hour before the test, as well as strenuous exercise before the test. Be sure to wear loose-fitting clothing to the test. Tighter clothing may restrict your breathing. You should also avoid wearing jewelry that might affect your breathing. If you wear dentures, wear them to the test to ensure that your mouth can fit tightly around the mouth piece used for the test. If you have had recent eye, chest, or abdominal surgery or a recent heart attack, you will likely need to delay the test until you have fully recovered. What happens during the tests?


Your PFT’s may include Spirometry, which measures the amount of air you breathe in and out. For this test, you’ll sit in front of a machine and be fitted with a mouthpiece. It’s important that the mouth piece fits snug so that all the air you breathe goes into the machine. You’ll also wear a nose clip to keep you from breathing air out through your nose. The respiratory technologist will explain how to breathe for the test. You may then breathe normally. Your doctor will ask you to breathe in and out as deeply or as quickly as you can for several seconds. They may also ask you to breathe in a medication that opens your airways. You’ll then breathe into the machine again to see if the medication affected your lung function.

Plethysmography Test:

A Plethysmography test measures the volume of gas in your lungs, known as lung volume. For this test, you’ll sit or stand in a small booth and breathe into a mouthpiece. Your doctor can learn about your lung volume by measuring the pressure in the booth. Diffusion Capacity Test: This test evaluates how well the small air sacks inside the lungs, called Alveoli, work. For this part of a pulmonary function test, you will be asked to breathe in certain gases such as Oxygen, Helium, or Carbon Dioxide. You may also breathe in a “Tracer Gas” for one breath. The machine can detect when you breathe out this gas. This will tests how well your lungs are able to transfer Oxygen and Carbon Dioxide to and from your blood stream.

Personal Note:

My Journey to the doctor I’ve been by myself for about a month now, no assistance in the home or when I go out and about. So going to the store or to my appointments are one of the most difficult challenges I face today. Especially when you are Oxygen dependent with Sarcoidosis, as well as Pulmonary Hypertension. Breathing is the center of my core, something that many people take for granted. I ventured out the other day to a couple of doctors appointments I had. I planned my whole schedule, with thoughts that I had everything down to a science. I would get there early and do valet parking, relying on the man to take my scooter out the car. I headed to my first appointment, only to find out that I had the wrong hospital. Which put me behind for the second appointment. The second appointment consisted of me doing a breathing test called Pulmonary function test. Which has been explained in the previous paragraphs. Once I knew I would be racing against time. I knew it would impossible to even do well, or as well as I would normally. So with great disappointment I headed back home. Many don’t begin to understand the disease nor the struggle that goes along with it. Without some type of personal assistance, life is very difficult.

ENCOURAGE YOURSELF: Be not discouraged, God will supply all that your needs, when needed. My hope is in my blessed Saviour. He is the author and finisher of my faith. Without God it would be impossible to continue on without knowing He is there for me. With much Love, Kate