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Preparing for any medical test can be nerve-wracking if you do not know what to expect. As such, it is a good idea to educate yourself about the test, as well as how to prepare for it, so you are ready when the time comes. Here is what you need to know about pulmonary function tests and how to prepare yourself before the test itself.
A pulmonary function test (PFT) is a noninvasive test that evaluates how well your lungs are working by measuring the amount of air in your lungs, as well as how effectively your lungs move air in and out. If you are having breathing problems, asthma or other chronic lung conditions, your health care provider may request a PFT test in order to measure the severity of your lung problems, diagnose lung disease or COPD or ascertain whether a specific treatment you have been on is working.
Depending on what your health care provider needs to find out, you may be asked to take a spirometry test, which involves breathing into a mouthpiece attached to a small electronic machine, or a plethysmography test, which involves sitting or standing inside an air-tight box the size of a small, square telephone booth. You may also require a blood-gas test or a diffusion capacity test (DLCO) to test how well your lungs transfer gasses. These tests measure how well your lungs are functioning by measuring your lungs’ volume, capacity, gas exchange and rates of flow.
A PFT test can measure a variety of lung volume values, offering your doctor a lot of helpful information about your lung function and condition. Your doctor will want to gather plenty of other health information first, however, as these test results must be interpreted based on your medical history and current physical health. Once all aspects of your health and your PFT test results are taken into account, your doctor can learn about your overall respiratory health and the progression of any lung disease, as well as get a better idea of how certain treatments and medications are working for you.
Here are the lung volume measures your doctor may want more information on, as well as what each of the lung volume measures means. In some cases, different measurements will be used to calculate other measurements for a full picture of your respiratory function and health.
Lung volume testing is typically indicated when a patient has an abnormal spirometry result, often indicating lung disease. Additional PFT testing is then ordered to confirm the presence of the suspected lung disease.
Normal values for your PFT test will vary, and are based on the average for someone of your same age, height, race and sex. Once conducted, your doctor will take all of these variables into account to determine whether you fall into a normal result range. If you are given multiple PFT tests, your results will also be compared to your previous test results.
Keep in mind that your lung capacity will decline somewhat as you get older. Lungs mature between the ages of 20 and 25. A healthy adult has a total lung capacity (TLC) of about six liters, which is comparable to about three large bottles of soda pop. However, around the age of 35, lung function begins to decrease slightly naturally, so some reduction in lung volume is to be expected even for healthy adults.
It is also important to note that variations in your results may be due to different technicians. As such, it may be helpful to ask about the technician’s experience level before your PFT test, just so you are aware of how much variation to expect in your results.
Before a PFT test, it is important to tell your doctor about any conditions, surgeries or medications that could affect your health during the test or affect the results of your test. If you have recently had eye, chest or belly surgery, you should not have a pulmonary function test until you are fully recovered. If you have recently had chest pain, a heart attack or any other heart condition, you should wait to conduct the test. Anyone with an aneurysm in the belly, brain or chest should not take this test. Patients with a cold, flu or active tuberculosis should also wait until they are feeling better before taking a PFT test. Additionally, patients who are pregnant, using bronchodilators or pain medications, or experiencing excessive tiredness or stomach bloating that could affect their ability to properly take a deep breath may have PFT results that are less accurate.
Once your doctor is aware of any conditions that could affect your health or the accuracy of your PFT test, wait to be cleared for the test. Once you are cleared, it is time to prepare for taking the test. Your health care provider will have specific instructions that are unique to your situation, but in general, you should:
In addition, you will be asked to sign a consent form to provide permission for the PFT test before it is conducted .
In all cases, you will be asked to wear unrestrictive clothing and jewelry. You will keep your dentures in place if you wear them, and you will be asked to empty your bladder before taking the test. During the test, remain as relaxed as you can. Your health care providers will watch for difficulty breathing, dizziness and other problems during and after the test. Following each test, you will be given an opportunity to rest and recover, particularly if you already struggle with breathing.
As you prepare for your PFT test, review these FAQs to make sure you are ready for your test and know what to expect when you go in for it.
You can! Just do not eat a large meal before testing since a full stomach can get in the way of your lungs inhaling to their fullest capacity. You will also want to avoid foods and drinks containing caffeine as they can dilate your airways and affect your test results.
Avoid smoking and exercising strenuously before a PFT test, as well as avoiding caffeine or eating a heavy meal. You may need to refrain from taking certain medications, too, as directed by your health care provider.
PFT tests assess how well your lungs are functioning and moving air, as well as helping to assess and diagnose certain breathing conditions like:
Certain things can affect the accuracy of a pulmonary function test, including:
In most cases, the test itself will take less than an hour to complete, depending on which tests your health care provider is administering to you. Sometimes, your health care provider is able to review the results with you as soon as the tests are finished. However, you may need to wait a few days for the full test results to come in, particularly if a blood test is involved.
A PFT test provides vital information to your health care provider about the health and function of your lungs. For patients receiving treatment for lung conditions, a pulmonary function test can tell health care providers how effective your current treatments are for your breathing. If you or a loved one are having difficulty breathing, or suspect that you have a lung condition or need additional treatment or medication, talk to your doctor about getting a PFT test today.
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