Sputum is mucous made by the lungs. It can be found deep in your airways. It contains lung tissue cells and other substances found in the lungs. It may be coughed up when you are ill.
This test may be done to find out whether there are cancer cells in your sputum. It may also be done to look for specific infections. It may be don in people who have lung cancer to see if the cancer is improving or coming back.
Using this test as a screening tool for lung cancer is not advised. Such screening does not appear to improve survival.
A sample of sputum will be collected. Usually it is collected after deep coughing to bring cells up from your lungs.
Sputum may also be collected during a bronchoscopy. This is a test in which a lighted tube is used to view the airways.
Clean your mouth before producing a sample by coughing.
If you are having a bronchoscopy:
You may be asked to breathe a humid vapor to help you to cough up sputum.
If you are able to produce enough sputum through coughing:
If you cannot produce enough sputum through coughing, your doctor may do a bronchoscopy:
Cytology is the study of cells in a sample. Some of your sputum will be smeared on a slide and studied under a microscope.
The procedures often take less than 1 hour.
There are no side effects to coughing sputum up.
If you had a bronchoscopy:
People who have general anesthesia may have some neck soreness for a few days.
It may take one to several days to get your results. It depends on how the sample was collected, where it was tested, and the health problem you may have.
It may take longer to get the results of samples being looked at for lung cancers.
The sputum may be cultured in people who are thought to have an infection. This lets bacteria, fungi, or viruses grow in a lab. It may show the exact cause of the infection.
This test can also be done to help diagnose:
Talk to your doctor about your test results. A test may point to an illness that you do not have. It can also miss an illness that you may have. The doctor will check your symptoms and all test results before making a diagnosis.
Lung cancer. Lab Tests Online—American Association of Clinical Chemistry website. Available at: https://labtestsonline.org/understanding/conditions/lung-cancer/start/3. Updated February 12, 2019. Accessed May 16, 2019
Lung cancer screening. EBSCO DynaMed website. Available at:http://www.dynamed.com/topics/dmp~AN~T901808/Lung-cancer-screening. Updated February 20, 2019. Accessed May 16, 2019.
Non-small cell lung cancer. EBSCO DynaMed website. Available at:http://www.dynamed.com/topics/dmp~AN~T114774/Non-small-cell-lung-cancer. Updated June 15, 2018. Accessed May 16, 2019.
Small cell lung cancer. EBSCO DynaMed website. Available at:http://www.dynamed.com/topics/dmp~AN~T115654. Updated June 15, 2018. Accessed May 16, 2019.
Last reviewed March 2019 by EBSCO Medical Review Board James P. Cornell, MD