Stool Tests

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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.

Collecting a stool sample is painless. Tell your child that it won't hurt but it must be done carefully. Kids who are old enough might be able to get a sample alone to avoid embarrassment. Go over the directions with your child so they can do this properly.

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

Why Are Stool Tests Done?

Most commonly, doctors order a stool test to check someone’s intestines for an infection by bacteria or parasites.

Some stool tests check for what the poop contains, such as fat. Normally, fat is absorbed from the intestine, and so poop contains almost no fat. In some types of digestive disorders, fat isn’t well absorbed and stays in the poop.

Stool tests can help doctors find many different types of problems, such as:

infection of the gastrointestinal system by some types of bacteria, viruses, or parasites
digestive problems, such as problems absorbing some types of sugars, fats, or nutrients
bleeding inside the gastrointestinal system
allergies or inflammation (for instance, from a milk protein allergy in infants)

Usually, disease-causing bacteria or parasites can be identified from one stool sample. Sometimes, though, a test can take up to three samples from different bowel movements (BMs). The doctor will let you know if this is the case.