Urea Breath Test for Pylori

Sample for Urea Breath Test for Pylori

• Two breath samples.

Purpose of the test (Indications) for Urea Breath Test for 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.

Introduction to 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 gram-negative organism is 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.

H. pylori infection pattern:

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 255 of the cases.

Mechanism of damage to gastric mucosa by H. pylori:

1. H.pylori inhabit the mucous 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. This 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 the H.pylori increases with age.
8. Most of these patients remain asymptomatic and never develop an ulcer.

The complications of H. pylori infection:

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

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.

1. Give orally radiolabelled urea (containing nonradioactive isotope ¹³C).
2. In gastric mucosa, if H.Pylori present then it will convert urea into  CO2 (¹³C).
3. This CO2 (¹³C) label passes through blood and goes to the lung.
4. Now measure CO2 (¹³C)  by:
   1. Gas chromatography.
   2. Mass spectrometer.
5. Procedure Two breath samples:
6. First, take a sample before giving the isotope-labeled (¹³C) urea.
7. Second after 30 minutes of a dose of isotope-labeled (13C) urea.
8. Specificity and sensitivity are 95%, and the test is cheaper to diagnose than invasive procedures.

Normal values of 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:

• The presence of IgG and IgA antibodies are seen in 81 to 100% of the patient with gastritis.
• But in only 25% of the patients without histological evidence of H. pylori.
• The testing of IgM is not helpful.

False-negative test:

1. You can get a false negative test if the patient uses antacids within a week prior to 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.

Diagnosis of H. pylori:

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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