Urea Breath Test for H. Pylori

What sample is needed for the Urea Breath Test for H. Pylori?

• Two breath samples.

What are the Indications for a Urea Breath Test for H. Pylori?

1. This test is used to detect Helicobacter Pylori infection.
2. Advised in patients with recurrent:
   1. Chronic gastritis.
   2. Duodenal ulceration.
   3. Duodenal inflammatory process.
3. Used for successful therapy.
4. It can determine if the infection is active.
5. Determining a cure within 4 to 6 weeks is a test of choice.
6. It can be used in children.

How will you define Helicobacter Pylori?

1. Helicobacter pylori (H.pylori) is a gram-negative bacillus. This was known as Campylobacter pylori.
2. It is S-shaped, curved, or gull-winged like Campylobacter.
3. This is a gram-negative organism found in the mucus covering the gastric mucosa.

4. These organisms are present next to the gastric lining cells of the surface and gastric pits.

What is the pattern of H. pylori infection?

1. H. pylori is associated with the following:
   1. Acute and chronic gastritis is seen in 90% of cases (70% to 100%).
   2. Duodenal ulcer is seen in 70% to 75% of the cases.
   3. Gastric ulcer is seen in 30% to 50% of the cases.
   4. Gastric carcinoma is seen in 20% to 25% of the cases.

What is the mechanism of damage to gastric mucosa by H. pylori?

1. H. pylori inhabit the mucus of the gastric mucosa.
2. These bacteria are found in the mucus of the gastric mucosa.
3. These bacteria cause damage to the mucosa, where HCL leads to ulcer formation.

4. H. pylori is also considered carcinogenic (class 1 gastric carcinogen).
5. The colonies of H.Pylori are seen in:
   1. Duodenal ulcer = 90% to 95% .
   2. Gastric ulcer = 60% to 70%.
   3. Gastric cancers = 20% to 25%.
6. Around 10% of the young, healthy people <30 years of age have the colonies of H. pylori.
7. Gastric colonization by H. pylori increases with age.
8. Most of these patients remain asymptomatic and never develop an ulcer.

What are the complications of H. pylori infection?

1. There is a risk of H. pylori infection leading to:
   1. Gastric ulcer.
   2. Chronic gastritis.
   3. Duodenal Ulcer.
   4. Ulcerative esophagitis.

What is the principle of the Urea Breath test for H. pylori?

1. H. pylori converts urea into  CO2 due to the presence of the urease enzyme.
2. Urea breath test uses oral ¹⁴C or ¹³C- labeled urea.
3. Radio-labeled CO2 was measured in breath before and after ingestion of labeled urea carbon in the presence of urease enzyme.

4. Give orally radiolabelled urea (containing nonradioactive isotope ¹³C).
5. In gastric mucosa, if H. Pylori present then it will convert urea into  CO2 (¹³C).
6. This CO2 (¹³C) label passes through blood and goes to the lungs.
7. Now measure CO2 (¹³C)  by:
   1. Gas chromatography.
   2. Mass spectrometer.

How will you perform Two breath samples?

4. First, take a sample before giving the isotope-labeled (¹³C) urea.
5. Second, after 30 minutes of a dose of isotope-labeled (13C) urea.
6. Specificity and sensitivity are 95%, and the test is cheaper to diagnose than invasive procedures.

What are the normal values of the urea breath test for H. pylori?

Breath test (Source 4)

• <50 DPM for H. pylori.
• 50 to 199 DPM for H. pylori
• >200 DPM positive for H. pylori.
• < 3 %.
• A positive test means H. Pylori infection.
• Source 1

Serology:

• IgG and IgA antibodies are present in 81% to 100% of the patients with gastritis.
• However, only 25% of the patients had no histological evidence of H. pylori.
• The testing of IgM is not helpful.

What are the possibilities of a False-negative test?

1. You can get a false negative test if the patient uses antacids within a week before the test.
2. The patient should not use any antibiotics and bismuth for one month.
3. No proton pump inhibitors and sucralfate for two weeks before the test.
4. The patient should be at rest during the collection of breath.

How will you diagnose the H. pylori infection?

The following tests can diagnose it:

1. Positive breath test.
2. Presence of specific antibody. Sensitivity is 94%, and specificity is 78%.
3. Positive culture.
4. A positive biopsy is done by endoscopy. Sensitivity is 93%, and specificity is 99%.
5. The stool is examined for the H. pylori antigen.

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