Stool gram stain

Alternative names:

feces gram stain; gram stain of stool

How the test is performed:

A sample of stool is applied in a very thin layer to a microscope slide. The specimen is stained with a violet stain then a red stain known as a gram stain and 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 for the test:

Adults and children:
There are many ways to collect the samples. You can catch the stool on plastic wrap that is loosely placed over the toilet bowl and held in place by the toilet seat. Then put the sample in a clean container. One test kit supplies a special toilet tissue that you use to collect the sample, then put the sample in a clean container.

Infants and young children:
For children wearing diapers, you can line the diaper with plastic wrap. If the plastic wrap is positioned properly, isolating the stool from any urine output, mixing of urine and stool can be prevented for a better sample.

How the test will feel:

Some people feel discomfort or embarrassment with this test.

Why the test is performed:

The test may be performed in an undiagnosed infection or illness involving diarrhea.