Stool Test: Bacteria Culture

What Are Stool Tests?

Testing a stool sample can help doctors find out what's going on when someone has a problem in the stomach, intestines, rectum, or other part of the gastrointestinal (GI) system.

Unlike most other lab tests, parents might need to collect the stool (feces or poop) sample for the test (also called a stool culture or fecal test). The doctor or lab will give instructions on how to do this.

Depending on the type of test, results can be back in 24–48 hours or take 3–4 days.

What Is a Stool Culture?

A stool culture helps the doctor see if there's a bacterial infection in the intestines.

Why Are Stool Cultures Done?

Doctors can order a bacteria stool culture to look for illness-causing such as:

• shigella
• salmonella
• yersinia
• campylobacter
• E. coli

Sometimes, the test finds other bacteria.

Doctors may order this test if a child has had diarrhea for several days, or has bloody diarrhea, (especially if there's been an outbreak of foodborne illness in the area), or recently traveled to certain places outside the United States.

Tell your doctor if your child recently took antibiotics.

How Is the Test Done?

At the lab, a technician places small stool samples in sterile plastic dishes with nutrients that encourage the growth of certain bacteria. These will grow only if they're already in the stool sample. If bacterial colonies form, the technician uses a microscope and chemical tests to identify them.

If no disease-causing bacterial colonies form, the test is negative. This means there’s no sign of a bacterial infection.

What if I Have Questions?

If you have questions about the stool culture or what the test results mean, talk to your doctor.