Helicobacter pylori antibody
Also called: H. pylori antibody, Helicobacter pylori IgG, H. pylori serology, H pylori
A blood test for antibodies against Helicobacter pylori, a stomach bacterium that causes ulcers and gastritis. A positive result shows the immune system has met the bacterium, but because antibodies persist after cure, a stool antigen or breath test is preferred to confirm a current, active infection.
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What does Helicobacter pylori antibody measure?
Helicobacter pylori is a bacterium that lives in the lining of the stomach and is a leading cause of peptic ulcers, chronic gastritis, and, over the long term, an increased risk of stomach cancer. This test detects antibodies (usually IgG) the immune system makes against H. pylori in the blood, which indicates the person has been infected. It was one of the original ways to detect the infection and is simple and widely available. Its major limitation, however, is that antibodies remain in the blood for months to years after the bacterium has been cleared — whether by treatment or naturally — so a positive antibody result cannot distinguish a current, active infection from a past one that is already gone. For that reason, the preferred tests to confirm an active infection, and to check that treatment has worked, are the stool antigen test and the urea breath test, which detect the bacterium itself rather than the body's memory of it. Antibody testing still has a role where those are not available, or as an initial screen, but a positive usually needs confirming with an active-infection test before treatment.
What does a high Helicobacter pylori antibody level mean?
- Current or past H. pylori infection — a positive result shows exposure; it cannot on its own tell an active infection from one that has already cleared.
- Untreated H. pylori — in a person not previously treated, a positive result more likely reflects a current infection worth confirming.
- The cause behind an ulcer or gastritis — supports H. pylori as the culprit when symptoms fit.
- Note — remains positive for months to years after successful treatment, so it is not used to confirm cure.
What does a low Helicobacter pylori antibody level mean?
- Negative — makes H. pylori infection unlikely and points away from it as a cause of symptoms.
- A recent infection not yet seroconverted — rarely, antibodies may not have developed yet very early.
When to discuss with a doctor
H. pylori testing is done when there is dyspepsia (upper-abdominal pain or discomfort), a proven or suspected peptic ulcer, or unexplained iron-deficiency anaemia, among other reasons. A positive antibody result supports H. pylori as a cause, but because antibodies persist long after the bacterium has gone, a stool antigen or breath test is preferred to confirm an active infection — and it is these active-infection tests, not the antibody, that are used to check treatment has worked. If active H. pylori is confirmed, it is treated with a course of antibiotics plus acid-suppressing medication (eradication therapy). Alarm features such as bleeding, weight loss, difficulty swallowing or vomiting need prompt assessment regardless. Mediora.AI shows an H. pylori result alongside blood count and iron studies so the ulcer-and-anaemia pattern is visible; confirming active infection and treatment belong with your doctor.