Lung Disease & Respiratory Health Center

How It Is Done

Home or office sample

Three sputum samples are usually collected over 3 days. Your doctor will give you a container to collect the sputum. This container may have a small amount of liquid (called fixative) in it. The fixative helps preserve the sample. Do not drink this liquid.

For best results, collect the sample in the morning right after waking up. Follow these steps:

• If you wear dentures, remove them before collecting the sample.
• Rinse your mouth with water.
• Take about four deep breaths followed by a few short coughs, then inhale deeply and cough forcefully into the container. Sputum is not the same as saliva, so make sure to get a sample of mucus from deep in your airway.

Carefully follow your doctor's instructions about where to deliver the sample. You may be instructed to take the sample to the doctor's office or to a laboratory. Deliver the sample soon after you obtain it. You may be instructed to refrigerate the sample if you are unable to deliver it immediately.

Bronchoscopy sample

See the topic Bronchoscopy for detailed information on how this procedure is done.

How It Feels

If you have discomfort when taking a deep breath or coughing, getting a sputum sample may be uncomfortable.

For information on how a bronchoscopy procedure feels, see the medical test Bronchoscopy.

Risks

Home or office sample

There is no risk linked with collecting a sputum sample at home or at your doctor's office.

Bronchoscopy sample

Bronchoscopy is generally a safe procedure. Although complications are rare, you should discuss the risks in your particular case with your doctor. Complications that may occur include:

• Spasms of the bronchial tubes. These can impair breathing.
• Irregular heart rhythms (arrhythmias).
• Infection, such as pneumonia. These usually can be treated with antibiotics.

Results

Sputum cytology examines a sample of sputum (mucus) under a microscope to determine whether abnormal cells are present. It may take several days to receive results from a sputum cytology.

Abnormal cells may indicate lung conditions such as pneumonia, inflammation, the buildup of asbestos fibers in the lungs (asbestosis), or lung cancer.

What Affects the Test

Reasons you may not be able to have the test or why the results may not be helpful include a sample that is too small; is dried out; contains only saliva; or is from nasal secretions, not your airway.

What To Think About

• There is a chance of false-negative test results with sputum cytology. This means that the test shows a lung condition is not present when it actually is present. Follow-up testing may need to be done if your symptoms continue.
• Sputum is not the same as saliva. It is important to obtain a sputum sample from deep in your airway. Collecting the sample in the morning, when you first wake up, is generally best.
• If you have trouble obtaining a good sample, try taking a hot shower first to help loosen the mucus in your airway.
• A sputum culture is a test to find and identify bacteria or fungi that are infecting the lungs or breathing passages. It is also done to identify the best antibiotic to treat a lung infection. For more information, see the topic Sputum Culture.
• Bronchoscopy or a needle lung biopsy are more commonly used than sputum cytology because the results provide more information about airway problems. For more information, see the topics Bronchoscopy and Lung Biopsy.