There are several methods to test for H pylori infection:
- Blood tests are used to measure antibodies to H pylori. Antibodies are proteins made by the body's immune system when it detects harmful substances such as bacteria. Blood tests for H pylori can only tell if your body has H pylori antibodies. It cannot tell if you have a current infection or how long you have had it.
This is because the test can be positive for years, even if the infection is cured. As a result, blood tests cannot be used to see if the infection has been cured after treatment.
- Breath Test (Carbon Isotope-urea Breath Test, or UBT) Up to 2 weeks before the test, you need to stop taking antibiotics, bismuth medicines such as Pepto-Bismol, and proton pump inhibitors (PPIs). During the test, you swallow a special substance that has urea. Urea is a waste product the body produces as it breaks down protein. The urea used in the test has been made harmlessly radioactive. If H pylori are present, the bacteria convert the urea into carbon dioxide, which is detected and recorded in your exhaled breath after 10 minutes. This test can identify almost all people who have H pylori. It can also be used to check that the infection has been fully treated.
- A stool test can detect traces of H pylori in the feces. This test can be used to diagnose the infection and confirm that it has been cured after treatment.