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Get Your Healthy Stomach BackDetecting and Eradicating H. pylori

Detecting H. pylori

Testing for H. pylori

What symptoms indicate that you should get tested for H. pylori?

Patients diagnosed with stomach and duodenal ulcers, gastritis, gastric MALT lymphoma, or idiopathic thrombocytopenic purpura (ITP), and those who have recently had endoscopic treatment for early gastric cancer can get tested under Japan’s national health insurance system. If you are concerned about a family history of gastric cancer or always seem to have stomach trouble, ask your doctor for advice. In Japan, you can get tested for H. pylori during your annual health check-up at your request and own expense.

Tests to Detect H. pylori

To detect H. pylori, both endoscopic methods and non-endoscopic tests can be used.

Methods that do not use an endoscope

The biggest advantage of non-endoscopic tests is that the people do not need to undergo an invasive endoscopy. Diagnoses by tests that do not use an endoscope are called sectional diagnoses, because they allow a diagnosis for the entire stomach.

Urea breath test
Patients take a diagnostic drug, and exhale into a collection device. Exhaled breath samples are collected before and after taking the drug to make a diagnosis. This is the most accurate test.
Antibody measurement
When people are infected with H. pylori, their bodies make antibodies to fight the bacterium. This test checks for the presence of antibodies in the blood or urine.
Rapid urease test
This method tests for the presence of H. pylori antigens in the stool.

Urea breath test

An enzyme produced by H. pylori, urease, breaks urea in the stomach down into ammonia and carbon dioxide. Carbon dioxide produced at the same time as ammonia by the breakdown of urea is quickly absorbed, moves from the blood to the lungs, and is exhaled in the breath as carbon dioxide gas. The urea breath test makes use of this principle. Patients take a test agent (13C-urea). If the patient is infected with H. pylori, the test urea will be broken down and a lot of 13CO2 will be detected in the breath. If the patient is not infected with H. pylori, the urea will not degrade, and so very little 13CO2 will be exhaled.

Carbon element (13C) exists in living organisms. It does not affect the human body.

There are 4 isotopes of carbon. Most carbon existing in nature is 12C, which accounts for about 98.9% of the total. It is a stable element with no radioactivity. The next most common isotope, 13C, also occurs in nature and accounts for about 1.1% of total carbon; it is this that is used as the test agent. As with 12C, 13C is a stable element with no radioactivity. As an example, the carbon content of an adult human body weighing60 kg is about 20% (12kg), and 13C is said to be about 1.1% (132g).

Endoscopic methods

An endoscopic examination method is called a “point diagnosis”, and it is carried out by collecting a sample of the gastric mucosa or stomach tissue. However, there is a risk of false diagnosis.

Microbial culture
A sample of stomach mucus membrane is taken, pulverized, and cultured for 5 to 7 days under conditions suitable for H. pylori, and then tested.
Rapid urease test
This method makes use of the activity of urease, an enzyme produced by H. pylori that breaks down urea. A sample of mucus membrane is added to a special reaction liquid to determine the presence of H. pylori, indicated by a change of color in the reaction liquid.
Direct microscopic count
In the histological examination method, a tissue sample of stomach mucus membrane is dyed with a special stain and a microscope is used to look for H. pylori.

H. pylori Eradication

To eradicate H. pylori, a proton pump inhibitor (PPI), which reduces the secretion of stomach acid, and two types of antibiotics are used. About 80% of patients are reported to have eradicated H. pylori successfully (H. pylori completely disappears from inside the stomach) after taking these three drugs for one week. Depending on the case, a drug to protect the mucus membrane of the stomach may also be used.

Importance of Post-Eradication Test

After the course of medication has been completed, it is very important to confirm that the H. pylori have been completely eradicated, as in some cases some bacteria may have survived the first course of treatment.

Post-eradication follow-up

Even when the eradication of the H. pylori is successful, the risk of stomach cancer will not be gone completely. This is because it takes time for the mucosa of the stomach to return to a normal condition, especially if the H. pylori infection was for a prolonged period. Because of this, it’s recommended to have a periodic endoscopic check-up following eradication.