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Stool Test: H. Pylori Antigen

Medically reviewed by: Larissa Hirsch, MD

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 an H. Pylori Test?

Helicobacter pylori (H. pylori) bacteria are a common cause of peptic ulcers (sores in the lining of the stomach, small intestine, or esophagus).

In this test, a stool sample is tested to check for H. pylori (pie-LOR-eye) antigens. Antigens (ANN-tih-jins) are substances that trigger the immune system to fight infection.

Why Are H. Pylori Tests Done?

Doctors may order an H. Pylori antigen stool test if a child has symptoms of a peptic ulcer, such as:

  • indigestion
  • belly pain
  • a full or bloated feeling
  • nausea
  • frequent belching (burping)
  • vomiting

An H. Pylori antigen test also can see if antibiotic treatment for an H. Pylori infection has worked.

For 2 weeks before the test, your child may be asked to avoid some types of medicines, such as antibiotics, antacids, bismuth, and peptic ulcer medicines such as proton pump inhibitors (PPIs) and H2 blockers.

How Is the Test Done?

At the lab, a technician puts a small amount of stool in tiny vials, then adds chemicals and a color developer. A blue color indicates the presence of H. pylori antigens.

What if I Have Questions?

If you have questions about the H. Pylori antigen test or what the test results mean, talk to your doctor.

Medically reviewed by: Larissa Hirsch, MD
Date reviewed: June 2023