The Helicobacter pylori (H. pylori) antigen stool test is a non-invasive stool test that looks for H. pylori antigens (protein markers from the bacteria) in a stool sample. Because it detects antigens from the organism itself, it is used to help identify an active H. pylori bacterial infection in the stomach and upper digestive tract.

H. pylori is a common cause of gastritis and can damage the stomach or duodenal lining, increasing the risk of stomach ulcers (peptic ulcer disease). This test supports ulcer diagnosis and evaluation of digestive issues such as abdominal pain, bloating, nausea, and ongoing indigestion.

What results generally mean:

Positive (antigen detected): H. pylori antigen is present, which strongly suggests a current, active infection. Your clinician may recommend treatment (often a combination of antibiotics and an acid-suppressing medicine) and may re-test later to confirm eradication.

Negative (antigen not detected): H. pylori is unlikely at the time of testing. If symptoms persist, your clinician may consider other causes of abdominal pain or digestive issues, or may repeat testing or choose a different test if there is high suspicion.

Important note: Some medications can reduce bacterial levels and lead to false-negative results. Your clinician may advise stopping certain medicines (such as proton pump inhibitors/acid blockers, antibiotics, or bismuth-containing products) for a period of time before sample collection, if it is safe for you.

This Helicobacter pylori stool test is commonly ordered when a clinician wants to evaluate symptoms or conditions that may be linked to H. pylori infection and related ulcer disease. It is widely used because it is accurate, practical, and non-invasive, without the need for endoscopy in many situations.

Your doctor may order this test if you have:

Ongoing upper abdominal pain (burning or gnawing discomfort), especially when associated with meals or occurring at night.

Persistent indigestion (dyspepsia), heartburn-like symptoms, early fullness, excessive burping, bloating, or nausea.

Symptoms suggesting an ulcer, such as recurrent stomach pain, poor appetite, or unexplained weight loss.

A history of stomach or duodenal ulcers or previously diagnosed H. pylori infection.

Follow-up after treatment: This test is frequently used to confirm that H. pylori has been cleared after therapy (a “test of cure”), typically performed several weeks after completing treatment, as directed by your clinician.

Why it matters: Detecting and treating H. pylori can relieve digestive symptoms, help heal ulcers, and reduce the chance of ulcer recurrence and complications such as bleeding. It also supports broader gastrointestinal health by identifying a treatable bacterial infection that may otherwise persist.

• Helicobacter pylori infection (active bacterial infection)
• Gastritis (inflammation of the stomach lining)
• Peptic ulcer disease (stomach ulcers and duodenal ulcers)
• Dyspepsia (chronic indigestion)
• Upper gastrointestinal bleeding related to ulcer disease
• Complications of ulcer disease (such as recurrent ulcers)

• Identifying a treatable cause of abdominal pain and ongoing digestive issues
• Supporting gastrointestinal health by diagnosing an active bacterial infection
• Helping with ulcer diagnosis and preventing ulcer recurrence
• Confirming successful treatment (a non-invasive “test of cure” after H. pylori therapy)
• Reducing the risk of ulcer-related complications (such as irritation, inflammation, and bleeding)