Sputum Exam for Mycobacteria

Alternate Names : Sputum Exam for Acid-Fast Bacilli

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 lab, 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.