Alternative Names sputum examination for acid-fast bacilli
Definition This test detects a bacteria called Mycobacterium in a sample of sputum.
Who is a candidate for the test? This test is done when tuberculosis or another kind of lung infection with Mycobacteria is suspected.
How is the test performed? The test is performed on a sample of sputum, or deep phlegm. The person must cough hard repeatedly to get the sputum up from the bottom of the lungs. When the sputum is in the throat and mouth, the person spits it into a container. In the laboratory, the sputum is placed on a microscope slide, stained, heated, and treated with acid. If Mycobacteria are seen, the sputum may be put on a culture dish to see if more organisms can be grown.
What is involved in preparation for the test? The doctor will provide specific instructions.
What do the test results mean? Normally, no Mycobacteria are observed. If the test is positive, the cause of the lung infection is Mycobacteria.
Author: David T. Moran, MD Reviewer: eknowhow Medical Review Panel Editor: Dr John Hearne Last Updated: 26/05/2005 Contributors Potential conflict of interest information for reviewers available on request
