Tests for Lung Disease Tests for Lung Disease
Lung function tests
Lung function tests can help your healthcare provider see how well your lungs are working. They may help diagnose certain lung conditions or diseases.
Pulse oximetry estimates oxygen levels in your blood. For this test, a probe will be placed on your finger or another skin surface such as your ear. It causes no pain and has few or no risks.
Spirometry is a type of lung function test that measures how much air you breathe out. It also measures how fast you can blow air out.
During the test, a technician will ask you to take a deep breath in. Then, you'll blow as hard as you can into a tube connected to a small machine. The machine is called a spirometer. Your healthcare team may have you inhale, or breathe in, medicine that helps open your airways and then blow into the tube again. They can then compare your test results before and after taking the medicine.
Some people feel lightheaded or tired from the required breathing effort.
Lung volume test
A lung volume test is a type of lung function test that measures how much air your lungs can hold.
Lung volume tests are the most accurate way to measure the volume of air in the lungs. It is similar to spirometry, except that you will be in a small room with clear walls. Or, you may breathe a special mixture of gases for a few minutes while wearing a clip on your nose. Some people feel lightheaded or tired from the breathing effort.
Lung diffusion capacity test
A lung diffusion capacity test assesses how well oxygen gets into the blood from the air you breathe.
For this test, you will breathe in and out through a tube for several minutes without having to breathe intensely. You also may need to have blood drawn to measure the level of hemoglobin in your blood.
Fractional exhaled nitric oxide (FeNO) tests
Fractional exhaled nitric oxide (FeNO) tests measure how much nitric oxide is in your breath. High levels of nitric oxide may mean that the airways in your lungs are inflamed, which can make it hard to breathe.
For this test, you will breathe out into a tube that is connected to the portable device. It requires steady but not heavy breathing and has few or no risks. It is done in adults and children age 5 and older.
Arterial blood gas test
An arterial blood gas test measures the oxygen and carbon dioxide levels in your blood.
Arterial blood gas tests are usually done in a hospital but may be done in a healthcare provider’s office. For this test, blood will be taken from an artery, usually in the wrist where your pulse is measured.
Lung imaging tests take pictures of the lung or its airways to help healthcare providers diagnose and monitor lung conditions.
A chest X-ray is a fast and painless imaging test to look at the structures in and around your chest.
This test can help diagnose and check conditions such as pneumonia, heart failure, lung cancer, tuberculosis, sarcoidosis, emphysema, and lung tissue scarring, called fibrosis. Healthcare providers may use chest X-rays to see how well certain treatments are working and to check for complications after certain procedures or surgeries.
The test may be done in the provider’s office, clinic, or hospital. You will stand, sit, or lie still for the test.
Chest X-rays have few risks. The amount of radiation used in a chest X-ray is very small. Talk to your provider if you are or could be pregnant.
Chest CT scan
A chest computed tomography (CT) scan is a painless imaging test that takes many detailed pictures, called slices, of your lungs and the inside of your chest. Computers can combine these pictures to create three-dimensional (3D) models that show the size, shape, and position of your lungs and the structures in your chest.
A chest CT scan can help figure out the cause of lung symptoms such as shortness of breath or chest pain. It can also tell your healthcare provider if you have certain lung problems, such as a tumor, excess fluid around the lungs that is known as pleural effusion, or pneumonia.
Your chest CT scan may be done in a medical imaging facility or hospital. You will lie still on a table and the table will slide into the scanner. You will hear soft buzzing or clicking sounds when you are inside the scanner and the scanner is taking pictures. You will be able to hear and talk to the technician performing the test while you are inside the scanner. For some diagnoses, a contrast dye, often iodine-based, may be injected into a vein in your arm before the imaging test.
In rare instances, some people have an allergic reaction to contrast dye. There is also a slight risk of cancer, particularly in growing children, because the test uses radiation. Although the amount of radiation from one test is usually less than the amount of radiation you are naturally exposed to over 3 years, patients should not receive more CT scans than what is recommended by clinical guidelines.
A chest magnetic resonance imaging (MRI) scan uses radio waves, magnets, and a computer to create pictures of the structures in your chest.
It can help your doctor diagnose lung problems such as a tumor or pleural disorder, blood vessel problems, or abnormal lymph nodes. A chest MRI can help explain the results of other imaging tests such as chest X-rays and chest CT scans.
A chest MRI may be done in a medical imaging facility or hospital. Before your test, a technician may inject a contrast dye into a vein in your arm to highlight your heart and blood vessels. You will lie still on a table, and the table will slide into the machine. You will hear loud humming, tapping, and buzzing sounds when you are inside the machine as pictures of your chest are being taken. You will be able to hear and talk to the technician performing the test while you are inside the machine.
Chest MRI has few risks. Talk to your healthcare provider and the technicians performing the test about whether you are or could be pregnant. Tell them if you have:
- A pacemaker or other implanted device, because the MRI machine can damage these devices
- Metal inside your body from previous surgeries because it can interfere with the MRI machine
- Metal on your body from piercings, jewelry, or some transdermal skin patches, because they can interfere with the MRI machine or cause skin burns
If you have tattoos you may feel some itching or swelling because older tattoo inks may contain small amounts of metal.
Bronchoscopy is a procedure that looks inside the lung airways. A bronchoscope is a tube with a light and a small camera. It is inserted through your nose or mouth down your throat, into your windpipe, and into your lungs.
This procedure is used to find the cause of a lung problem. It can identify tumors, signs of infection, excess mucus in the airways, bleeding, or blockages in the lungs. It also can allow your doctor to take samples of mucus or tissue for other laboratory tests, as well as to insert airway stents, or small tubes, to keep your airway open and treat some lung problems.
Before the procedure, you will be given medicine to relax you. A liquid medicine also will be given to numb your nose and throat. You may experience a sore throat, cough, or hoarseness for a few days.
Bronchoscopy is usually safe, but there is a small risk of fever or minor bleeding. Pneumothorax, or collapsed lung, is a rare but serious side effect that can be treated. Your doctor may do a chest X- ray after the procedure to check for lung problems.