Alternate Names: Gram stain of sputum

How Performed: A sample of sputum is applied in a very thin layer to a microscope slide. The specimen is stained with a violet stain known as a gram stain and then examined under the microscope for the presence of bacteria. The color, number, and morphologic appearance of the cells make it possible to identify the genus of the organism.

How To Prepare: Obtain a sputum sample from your lungs by coughing into a specimen container. If coughing does not produce sputum, a breathing treatment may precede the test to induce sputum production.

How It Feels: The person needing the test will usually have a productive cough. Occasionally, the sputum is collected by bronchoscopy, and more discomfort is associated with this procedure.

Risks: There are no risks unless a bronchoscopy is used to obtain the specimen.

Why Performed: The test is performed when there is a persistent or prolonged cough, sputum has a foul odor or unusual color, respiratory disease is suspected, or there is a generalized infection.

Normal Values: No presence of organisms is normal. The sputum is clear, thin, and odorless.

Abnormal Results: A bacterial infection may be present. The infecting organism may be identified.

Cost:

Special Considerations: The test may need to be repeated if the specimen produced contains only saliva from the mouth.